98 LX Radio and Speaker Install (2 Viewers)

[drjman]

On almost every vehicle I have owned I have replaced the radio head unit and all the speakers. Its an easy and inexpensive way to get a lot better sound than stock, especially on an 18 year old truck. I'm not an audiophile and if you are one, you might want to look away!

I set out to first install the speakers and tweeters since my head unit is a couple days behind in shipping. I was planning on rewiring all of them from the doors to the head unit, bypassing the stock amp and using the head unit to power them all. I have done this before on a Scion XB and 2004 Tundra Double Cab, its not fun! When searching for the wiring diagrams and info here, I found out that the speaker wires were the same color from the head unit to the stock amp and still the same color from the stock amp to the speakers. Score! I will just connect everything where the amp is so I don't have to rewire the whole thing!

As of right now, i'm not going to be using the stock sub-woofer or putting in a new one. Increasing the speaker size should add some better mid/bass and honestly, the stock sub didn't do anything noticeable anyways.

Parts:
Pioneer FH-X720BT ($100)

Pyle PL63BL 6.5-Inch 360-Watt 3-Way Speakers (2 Pair) ($16 ea pair)(My LX had 5.25 speakers, so these barely fit)

Power Acoustik NB-2 200-Watt 3-Way Tweeters ($10)(built in crossover)

DKM Double Din Radio DVD Stereo Frame for Lexus Lx-470 ($30)

CURT 59421 22-16 Ga Butt Connectors 100 Per Bag ($9)

PART 1 - Bypassing the amp
1. Remove all the door panels (Door panel removal process)

2. Remove the passenger seat (4 bolts, unplug the harness)

3. Remove the Pioneer stock amp (4 bolts on floor, 2 screws on each side of holding bracket)

4. Orange Plug is harness "D", white plug in green receiver is harness "B", grey plug is harness "C", white plug in white receiver is harness "A"

Left to Right : A - C - B - D

Harness Pin and wire Guide
(Thanks to @nikramos Help - LX stereo wiring clarification, I also fixed the lettering based on the actual wiring diagram)

Harness D:
01 BRN GND1
02 BLU/YEL +B1 (from 20A radio fuse)
03 n/c
04 BRN GND2
05 BLU/YEL +B2 (goes to Head unit)
06 GRY ACC (goes to 15A Cigar fuse)
07 ORG MUTE
08 GRY ACC0 (goes to head unit)
09 WHT +B0

Harness B (wires going from amp to speakers):
01 LT GRN FR+
02 PNK FL+
03 n/c
04 RED RR+
05 BLK RL+
06 BLU FR-
07 VIO FL-
08 n/c
09 n/c
10 n/c
11 n/c
12 WHT RR-
13 YEL RL-

Harness C (wires going to subwoofer):
01 BLU/BLK WF1+
02 BLU/RED WF1-
03 n/c
04 n/c
05 n/c
06 BLU/WHT WF2+
07 BLU/YEL WF2- (I actually used this on instead of D5 and it still worked?)
08 n/c
09 n/c
10 n/c
11 n/c
12 n/c
13 n/c
14 n/c

Harness A (wires coming from the head unit, same coloring at head unit harness):
01 n/c
02 n/c
03 LT GRN FR+
04 BLK RL+
05 RED RR+
06 BLK/RED AMP
07 GRN BEEP
08 BLU FR-
09 VIO FL-
10 PNK FL+
11 NCA SDG1
12 NCA SDG2
13 YEL RL-
14 WHT RR-

We are only concerned with the bolded, red text colored wires

5. Cut the wires on harness "B" leaving about an inch or so left on the plug in case you need to reuse it.

6. Strip and put the pink butt connectors (16-22awg sized) on each of the wires and crimp them down. Tug on it to make sure they are on there (not too hard).

7. Cut out the correct wires from harness "A" and strip the ends

8. Connect the stripped end of the harness "A" wires to the corresponding color that already has the butt connector. Most vehicles I have worked on change the colors from one harness to the next on the same path, so this was refreshing!

9. Now we need to make sure that the constant 12v and ACC 12v gets to the head unit. Both of those wires go to the amp first, then on to the head unit. I searched for which specific wires they were on the forum, but there wasn't a good answer. I got a little help from AllData and figured it out. There are two Blue/Yellow wires and two Grey wires. They both need to be connected/jumped respectively to make sure power gets to the head unit.

Connect D5 and D2 (both Blue/Yellow) together with a butt connector (constant 12v).
Connect D6 and D8 (both Grey) together with a butt connector (ACC 12).

10. That takes care of bypassing the amp and now the speaker wires connect straight from the head unit to the speakers in the doors!

PART 2 - Installing 6.5 inch speakers into 5.25 housing

These Pyle speakers are the number one selling 6.5 inchers on Amazon with great reviews. They aren't Polk or Infinity's but they should be a big improvement over the paper stock speakers and give a little more bass than the 5.25 inch stocks. When you remove the stock speakers, the connectors inside are plug and play with the new speakers using the existing wiring (bypassing the amp from Part 1).

1. With the door panels off, unscrew the three screws holding the stock 5.25 inch speakers to the door box.

2. I reused those three screws and screwed them back into the plastic speaker box making new holes. Be careful not to tighten them flush since the 6.5 inch speaker will bend on the back side since it doesn't fit flush in the opening.

3. Here is the finished product. It is in there snug and tight and it fits behind the door panel perfectly.

4. Repeat the above steps for the other doors (front and rear)

PART 3 - Replacing the stock tweeters

These ended up sounded like s***e! I disconnected them and everything sounds fine. They were $10, so oh well. This section still applies, just get something else!

I purchased these tweeters because they were cheap and had the built in crossover. I didn't want to spend the money on a true component system. I really just wanted some sound coming from higher up to balance our the low placed speakers. I have replaced door speakers like this before and disconnected the A panel tweeter and I could really tell the sound was coming from below and not "everywhere". Its a cheap way to get the best out of the whole system.

1. Remove the tweeter bracket by removing the single screw. Unplug the tweeter harness (black/yellow wiring to white plug)

2. I had to twist the tweeter and the bracket in opposite directions to get the tiny screw unstuck that connects the tweeter to the bracket.

3. Here is the bracket fully removed with the new tweeter.

4. For these specific aftermarket tweeters, the stripped wiring is as follows:
Silver = - negative
Copper = + Positive

5. The stock tweeter wires are as follows:
Black = - negative
Yellow = + positive

5. Strip all wires and connect with pink butt connectors. I had to strip the tweeter wires twice as long as normal so they can be folded in half to make them better fit the connector.

6. The finished product:

7. The tweeters come with adhesive stickers for mounting. I used those to attach them to the bracket and they held really well.

8. Mount the new tweeter back and it should look like this: (it fits behind the cover with no problem and is directed properly)

While I was typing this up, my head unit showed up a day early! I'll be putting that in tonight and will continue the write up with that installation and the final results soon.

 

[drjman]

PART 3 - Head Unit Installation

1. To save time, I always take the new head unit's harness out of the box and splice and attach butt connectors to each wire. Its a lot more comfortable to do this on the couch rather than hunched over in the truck.

2. First, carefully remove the trim panel and HVAC combo. I put electrical tape on a large flat head to get started, then slowly pried it out by hand.

3. Remove the 4 screws that mount the head unit to the dash.

4. Remove both brackets (4 screws each on both sides of the stock head unit) and save them to reuse on the new head unit (if you're using a double din).

5. Now we need to cut off a good chunk of that plastic shielding to expose the wires.

6. Using the wiring guide for my head unit and the stock wiring guide, I found each corresponding stock wire and cut them.

Stock Wiring at OEM head unit (Bold Red is what i used):
01 WHT +B
02 BLU/YEL +B2
03 n/c
04 GRN ILL
05 BLK/RED ANT+
06 PNK FL+
07 n/c
08 RED RR+
09 BLK RL+
10 GRY ACC
11 BRN E (ground)
12 n/c
13 WHT/GRN ILL
14 BLK/RED AMP+
15 ORG MUTE
16 GRN BEEP
17 BLU FR-
18 LT GRN FR+
19 VIO FL-
20 n/c
21 WHT RR-
22 YEL RL-

You can see that the same white shielding seen by the amp is the same up by the head unit.

7. Make sure you have the right wires and start connecting them. Here are the non-speaker wires:

Here's everything connected:

8. My head unit came with a microphone. I removed the black panel above the ignition and routed the wire under it and over behind the head unit. I was able to clip the mic onto the instrument panel side.

9. This is where I like connect the head unit and test everything before putting it all back together. Here is my test sequence.

a. Power it on, save a radio station, turn off and remove key, turn back on and make sure radio station saved. (If you swapped the constant and ACC wires, you would lose settings every time you turn off the truck).

b. Check to see if the dimmer works (if equipped)

c. Make sure the Antenna or amp is getting the power up signal (if equipped)

d. Test all speakers. Use the Fade and Balance to isolate and make sure each speaker is working and in the correct location.

10. If all of those tests pass, attach the brackets to the new head unit and mount it in the dash (you should have 8 bracket screws and 4 dash mount screws from existing). Attach the HVAC plugs to the trim panel and snap it all back in!

11. Turn it back on and enjoy! (my custom trim panel is coming tomorrow. excuse the gap)

 

[Phat1842Many]

Looks killer. Thanks for the great write-up. A man after my own heart. I will eventually do just this, maybe adding an amp.

Please post a pic when you have the trim installed. And let us know how you like the new deck.

Cheers

Phat-

 

[atomsk]

Let me know how the mic ends up doing right there. That spot looks great, and I'm trying to decide where I'll put mine.

 

[drjman]

Let me know how the mic ends up doing right there. That spot looks great, and I'm trying to decide where I'll put mine.

I haven't tested while driving but it sounded pretty clear during my tests.


Sent from my iPhone

 

[drjman]

Looks killer. Thanks for the great write-up. A man after my own heart. I will eventually do just this, maybe adding an amp.

Please post a pic when you have the trim installed. And let us know how you like the new deck.

Cheers

Phat-

For $100 the deck is great. More than enough power for the speakers. Eventually adding a sub will help out with the lows. It's great overall though.
My trim piece was just delivered.


Sent from my iPhone

 

[drjman]

PART 3 - Double Din Fill Bracket

I finished putting this in right now. It came in a white box with no instructions and it definitely needed to be secured to the HVAC panel.

1. I pulled the panel off and laid it face down. It was easier to pull it out with the nice big gaps on the side of the head unit.

2. The bracket does fit pretty well and there's a little ledge all the way around the back of the face plate that it sits in nicely. This is it resting on top. Not secured.

Here's a close up of where it sits:

3. At first, I laid it in there and just snapped the face plate back up there to see what would happen (since there were no instructions). It falls back a little bit and this is where I found out I was going to have to tape, glue or screw this thing in to place. Since I'm never going back to the stock head unit, making this permanent was no big deal.

4. I decided to use the only joining compound I had laying around at the moment: Goop

I put a long line of it on the bottom of the frame so the entire bottom of the bracket would be sitting in it and completely join to the HVAC plate (Red line). I also put a large glob on each top corner (red arrows).

I let it sit for a while like that so that it would start to join. Once it was attached well enough (gave it a wiggle to check), I put the whole HVAC plate back in place. Here's the finished product.

it looks pretty good. Like it was meant to be that way. The bracket itself is really sturdy. It doesn't flex at all like those crappy Metra brackets. For $30 and some careful gluing, this looks great.

 

[NC-Grayson]

Thank you for this awesome DIY that I just stumbled upon!

 

[LBridges]

Excellent write-up. Do you recall how large the opening is on the door pods? I just pulled one as the PS speaker is crackling, and the opening is ~4.5 inches, and there is only a bit more than 2" depth available. This is against my 2000 LX, but the black speaker pods look the same. I'm thinking of going with some 5.25" Type S speakers from Alpine - looking like they should drop in with no further mods needed.

 

[PabloCruise]

On almost every vehicle I have owned I have replaced the radio head unit and all the speakers. Its an easy and inexpensive way to get a lot better sound than stock, especially on an 18 year old truck. I'm not an audiophile and if you are one, you might want to look away!

I set out to first install the speakers and tweeters since my head unit is a couple days behind in shipping. I was planning on rewiring all of them from the doors to the head unit, bypassing the stock amp and using the head unit to power them all. I have done this before on a Scion XB and 2004 Tundra Double Cab, its not fun! When searching for the wiring diagrams and info here, I found out that the speaker wires were the same color from the head unit to the stock amp and still the same color from the stock amp to the speakers. Score! I will just connect everything where the amp is so I don't have to rewire the whole thing!

As of right now, i'm not going to be using the stock sub-woofer or putting in a new one. Increasing the speaker size should add some better mid/bass and honestly, the stock sub didn't do anything noticeable anyways.

Parts:
Pioneer FH-X720BT ($100)

Pyle PL63BL 6.5-Inch 360-Watt 3-Way Speakers (2 Pair) ($16 ea pair)(My LX had 5.25 speakers, so these barely fit)

Power Acoustik NB-2 200-Watt 3-Way Tweeters ($10)(built in crossover)

DKM Double Din Radio DVD Stereo Frame for Lexus Lx-470 ($30)

CURT 59421 22-16 Ga Butt Connectors 100 Per Bag ($9)

PART 1 - Bypassing the amp
1. Remove all the door panels (Door panel removal process)

2. Remove the passenger seat (4 bolts, unplug the harness)

3. Remove the Pioneer stock amp (4 bolts on floor, 2 screws on each side of holding bracket)

4. Orange Plug is harness "D", white plug in green receiver is harness "B", grey plug is harness "C", white plug in white receiver is harness "A"

Left to Right : A - C - B - D

Harness Pin and wire Guide
(Thanks to @nikramos Help - LX stereo wiring clarification, I also fixed the lettering based on the actual wiring diagram)

Harness D:
01 BRN GND1
02 BLU/YEL +B1 (from 20A radio fuse)
03 n/c
04 BRN GND2
05 BLU/YEL +B2 (goes to Head unit)
06 GRY ACC (goes to 15A Cigar fuse)
07 ORG MUTE
08 GRY ACC0 (goes to head unit)
09 WHT +B0

Harness B (wires going from amp to speakers):
01 LT GRN FR+
02 PNK FL+
03 n/c
04 RED RR+
05 BLK RL+
06 BLU FR-
07 VIO FL-
08 n/c
09 n/c
10 n/c
11 n/c
12 WHT RR-
13 YEL RL-

Harness C (wires going to subwoofer):
01 BLU/BLK WF1+
02 BLU/RED WF1-
03 n/c
04 n/c
05 n/c
06 BLU/WHT WF2+
07 BLU/YEL WF2- (I actually used this on instead of D5 and it still worked?)
08 n/c
09 n/c
10 n/c
11 n/c
12 n/c
13 n/c
14 n/c

Harness A (wires coming from the head unit, same coloring at head unit harness):
01 n/c
02 n/c
03 LT GRN FR+
04 BLK RL+
05 RED RR+
06 BLK/RED AMP
07 GRN BEEP
08 BLU FR-
09 VIO FL-
10 PNK FL+
11 NCA SDG1
12 NCA SDG2
13 YEL RL-
14 WHT RR-

We are only concerned with the bolded, red text colored wires

5. Cut the wires on harness "B" leaving about an inch or so left on the plug in case you need to reuse it.

6. Strip and put the pink butt connectors (16-22awg sized) on each of the wires and crimp them down. Tug on it to make sure they are on there (not too hard).

7. Cut out the correct wires from harness "A" and strip the ends

8. Connect the stripped end of the harness "A" wires to the corresponding color that already has the butt connector. Most vehicles I have worked on change the colors from one harness to the next on the same path, so this was refreshing!

9. Now we need to make sure that the constant 12v and ACC 12v gets to the head unit. Both of those wires go to the amp first, then on to the head unit. I searched for which specific wires they were on the forum, but there wasn't a good answer. I got a little help from AllData and figured it out. There are two Blue/Yellow wires and two Grey wires. They both need to be connected/jumped respectively to make sure power gets to the head unit.

Connect D5 and D2 (both Blue/Yellow) together with a butt connector (constant 12v).
Connect D6 and D8 (both Grey) together with a butt connector (ACC 12).

10. That takes care of bypassing the amp and now the speaker wires connect straight from the head unit to the speakers in the doors!

PART 2 - Installing 6.5 inch speakers into 5.25 housing

These Pyle speakers are the number one selling 6.5 inchers on Amazon with great reviews. They aren't Polk or Infinity's but they should be a big improvement over the paper stock speakers and give a little more bass than the 5.25 inch stocks. When you remove the stock speakers, the connectors inside are plug and play with the new speakers using the existing wiring (bypassing the amp from Part 1).

1. With the door panels off, unscrew the three screws holding the stock 5.25 inch speakers to the door box.

2. I reused those three screws and screwed them back into the plastic speaker box making new holes. Be careful not to tighten them flush since the 6.5 inch speaker will bend on the back side since it doesn't fit flush in the opening.

3. Here is the finished product. It is in there snug and tight and it fits behind the door panel perfectly.

4. Repeat the above steps for the other doors (front and rear)

PART 3 - Replacing the stock tweeters

These ended up sounded like s***e! I disconnected them and everything sounds fine. They were $10, so oh well. This section still applies, just get something else!

I purchased these tweeters because they were cheap and had the built in crossover. I didn't want to spend the money on a true component system. I really just wanted some sound coming from higher up to balance our the low placed speakers. I have replaced door speakers like this before and disconnected the A panel tweeter and I could really tell the sound was coming from below and not "everywhere". Its a cheap way to get the best out of the whole system.

1. Remove the tweeter bracket by removing the single screw. Unplug the tweeter harness (black/yellow wiring to white plug)

2. I had to twist the tweeter and the bracket in opposite directions to get the tiny screw unstuck that connects the tweeter to the bracket.

3. Here is the bracket fully removed with the new tweeter.

4. For these specific aftermarket tweeters, the stripped wiring is as follows:
Silver = - negative
Copper = + Positive

5. The stock tweeter wires are as follows:
Black = - negative
Yellow = + positive

5. Strip all wires and connect with pink butt connectors. I had to strip the tweeter wires twice as long as normal so they can be folded in half to make them better fit the connector.

6. The finished product:

7. The tweeters come with adhesive stickers for mounting. I used those to attach them to the bracket and they held really well.

8. Mount the new tweeter back and it should look like this: (it fits behind the cover with no problem and is directed properly)

While I was typing this up, my head unit showed up a day early! I'll be putting that in tonight and will continue the write up with that installation and the final results soon.

Thank you! I have a '99 LX, and as you know, we are SOL on harness adapters. So for right now I have been rocking out on the tape deck and hoping the Nakamichi doesn't eat my CDs, but I know that the time is coming when an updated head unit will really add to the vehicle.

 

[PabloCruise]

PART 3 - Head Unit Installation

1. To save time, I always take the new head unit's harness out of the box and splice and attach butt connectors to each wire. Its a lot more comfortable to do this on the couch rather than hunched over in the truck.

2. First, carefully remove the trim panel and HVAC combo. I put electrical tape on a large flat head to get started, then slowly pried it out by hand.

3. Remove the 4 screws that mount the head unit to the dash.

4. Remove both brackets (4 screws each on both sides of the stock head unit) and save them to reuse on the new head unit (if you're using a double din).

5. Now we need to cut off a good chunk of that plastic shielding to expose the wires.

6. Using the wiring guide for my head unit and the stock wiring guide, I found each corresponding stock wire and cut them.

Stock Wiring at OEM head unit (Bold Red is what i used):
01 WHT +B
02 BLU/YEL +B2
03 n/c
04 GRN ILL
05 BLK/RED ANT+
06 PNK FL+
07 n/c
08 RED RR+
09 BLK RL+
10 GRY ACC
11 BRN E (ground)
12 n/c
13 WHT/GRN ILL
14 BLK/RED AMP+
15 ORG MUTE
16 GRN BEEP
17 BLU FR-
18 LT GRN FR+
19 VIO FL-
20 n/c
21 WHT RR-
22 YEL RL-

You can see that the same white shielding seen by the amp is the same up by the head unit.

7. Make sure you have the right wires and start connecting them. Here are the non-speaker wires:

Here's everything connected:

8. My head unit came with a microphone. I removed the black panel above the ignition and routed the wire under it and over behind the head unit. I was able to clip the mic onto the instrument panel side.

9. This is where I like connect the head unit and test everything before putting it all back together. Here is my test sequence.

a. Power it on, save a radio station, turn off and remove key, turn back on and make sure radio station saved. (If you swapped the constant and ACC wires, you would lose settings every time you turn off the truck).

b. Check to see if the dimmer works (if equipped)

c. Make sure the Antenna or amp is getting the power up signal (if equipped)

d. Test all speakers. Use the Fade and Balance to isolate and make sure each speaker is working and in the correct location.

10. If all of those tests pass, attach the brackets to the new head unit and mount it in the dash (you should have 8 bracket screws and 4 dash mount screws from existing). Attach the HVAC plugs to the trim panel and snap it all back in!

11. Turn it back on and enjoy! (my custom trim panel is coming tomorrow. excuse the gap)

I just dug into this thread for a more detailed reading. It looks like your '98 does not use the Nakamichi head unit?

From here, it looks like the base LX head unit has a 20 pin connector, while Nakamichi head unit has a 22 pin connector: Stereo Wiring: Land Cruiser / LX 470 (1998-02)

 

[richardrichss]

Thanks for your detailed information here. With what you detailed and the links you provided, I am on my way to musical bliss. I am doing things a little different. I am using the preamps on the new stereo I purchased, using RCAs to connect to my new amps powering my 6.5" Kickers and twin 12" Jensen DUB speakers. Call it a mid life crisis of sorts. I suppose it's better than a new girlfriend or an expensive convertible.

A WORD OR WARNING to anyone considering doing this install--I ordered the EXACT stereo frame you have a link to from Amazon last month. I just started my install today and as is my luck, the wrong frame was sent to me. I suppose it was my fault for not looking at it closer as I was just stacking parts in my garage as they came. The listing shows the correct one. I am hoping for some mercy from the seller as the return window has passed. I am a little nervous to order another one from the same seller until I hear back from them. I'll just have a hole around my stereo for a bit while things get sorted out!

Thanks again for your write up.

 

[ClassyJalopy]

Just installed a Hizpo Android unit: https://www.amazon.com/gp/product/B07H9WR97B

The instructions were spot on. This unit also had a lead to provide a ground when parking brake is engaged. I suppose that is used as a safety measure to keep drivers from being distracted. I just shorted it directly to the ground and problem solved.

Thank you for detailed DIY - it helped do my very first stereo install successfully.

 

[drjman]

I just dug into this thread for a more detailed reading. It looks like your '98 does not use the Nakamichi head unit?

From here, it looks like the base LX head unit has a 20 pin connector, while Nakamichi head unit has a 22 pin connector: Stereo Wiring: Land Cruiser / LX 470 (1998-02)

It was not a Nakamichi, or at least, not the same as in later years.

 

[fanboy]

This is an amazing, magisterial thread.

I have a 2001 LX470 with the same head unit as OP shows.

Can I replace only the speakers in my truck? Would off-the-shelf speakers work as plug-and-play replacements if I leave the current head unit and amp in place? I'd get 5.25" just to make things easy.

 

[Roosevelt T]

I just dug into this thread for a more detailed reading. It looks like your '98 does not use the Nakamichi head unit?

From here, it looks like the base LX head unit has a 20 pin connector, while Nakamichi head unit has a 22 pin connector: Stereo Wiring: Land Cruiser / LX 470 (1998-02)

Did you tackle this with the 22 pin? Seems straight forward by using the TLCFAQ schematic and then the corresponding wires the OP used (albeit different pins locations).

That being said I will rip a vehicle apart mechanically, but electrical stuff is not my forte, so I figured I'd bump the thread and ask.

 

[PabloCruise]

Did you tackle this with the 22 pin? Seems straight forward by using the TLCFAQ schematic and then the corresponding wires the OP used (albeit different pins locations).

That being said I will rip a vehicle apart mechanically, but electrical stuff is not my forte, so I figured I'd bump the thread and ask.

I did!
I have a thread in here about wiring up the connector.

 

[Roosevelt T]

I did!
I have a thread in here about wiring up the connector.

Reading through your posts and threads, it seems like your goals were different than OP's though as you wanted to keep the OEM connectors, am I correct?

Edit: Finally found your main thread, wasn't showing on the phone. Seems like your 22 pin schematic will still help if you want to follow this thread as well, thanks!

 

[Greenbean]

This is an amazing, magisterial thread.

I have a 2001 LX470 with the same head unit as OP shows.

Can I replace only the speakers in my truck? Would off-the-shelf speakers work as plug-and-play replacements if I leave the current head unit and amp in place? I'd get 5.25" just to make things easy.

I doubt it but am not 100% sure...

The issue is that most OEM speakers have a different Ohm rating than most aftermarket spears do. That's why you rarely see people just swap in "better" speakers on a factory amp. IIRC the lower Ohm rating of many factory speakers (2-ohm)??? means the amp can be rather "wimpy"

Truly the best thing is to bypass the factory amp.

Again I may be off a bit, It's been a decade+ since I dove into car audio like I used to back in my Hay-Day!

 

[JOSHD]

I just replaced the Head Unit and speakers in my 1999 LX470 with Nakamichi 6 disc and Amplifier. I can attest that all the Speakers in this system are 4 ohm speakers. They are all actually marked 4 ohm on the back and if you put them on Fluke they measure ~3.87 or so ohms.