So this mod is about $143 ($71.50/door) but well worth it. I had to replace my ML 6x9s so I figured I may as well do the other speakers too while I had the door panels off. All are 8ohm and require very little modification, in the case of the mid and tweeters I even used the stock brackets. Took about three hours. Watch online videos on how to remove door panels, if you don't know how, very easy. Update - Added sub upgrade below.
Speakers -
6x9 woofers - got these from another post. $57.97
https://www.amazon.com/gp/product/B00N8077VY/ref=oh_aui_detailpage_o06_s01?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B0002BBP7Y/ref=oh_aui_detailpage_o06_s01?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B00IIC6CPE/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1
2" midrange - Picked mainly for their size but sound very decent. Clip or unsolder and reuse harness and bracket. Used some machine screws, washers and nuts to hold the speakers in the brackets. $17.95
https://www.amazon.com/gp/product/B0008JHBOQ/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1
1" tweeters - unsolder harness, re-use cap and bracket. You have to clip off a small plastic piece but the new tweeter snaps right in. I used some super glue just to make sure it stays put. These are the most expensive component but well worth it. $66.75
https://www.amazon.com/gp/product/B00EO76ZGS/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1
So much better than stock.
UPDATE: Went back in to apply Dynamat all over the doors. The improved bass was causing rattles and vibrations on the doors. Applied Dynamat all over the door and behind the 6x9 drivers. Much better. Amazing improvement over stock ML speakers and keeps getting better.
UPDATE2: Went back in and put 199uF caps on the 6x9s to limit the bass a bit as it was still shaking the door panels. I think the speaker grills are too restrictive and keeping air behind the panel.
UPDATE3: Since I was in audio upgrade mode, I ripped out the useless 6" sub box and put in a external 8" wired to the same stock amp (just extended wire out, box sits behind passenger second row seat pointing to back of truck). This sub driver is made for small enclosures as I didn't want a huge box back there. Its a 8" driver but requires a 9" hole in the box and a 10" grill. Really deep and punchy bass even from the stock amp. Doesn't come in under $100 but wanted to keep this all together. So happy with this setup.
"Tang Band W8-2022 8" RBM Subwoofer 8 Ohm" from www.parts-express.com!
https://www.amazon.com/gp/product/B003LYL4R0/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B00N4918A0/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1