Thought would get back to you after installing my US Spect PA12-Toy unit last Friday.
1. I recommend getting right tools to remove the dash panels. Made it very easy, and no damage at all.
2. For '04, I didn't realize that the vent panels come off first, then un-bolt the Nav/Tape player.
3. I found it was easier to fully disconnect all the Nav/Tape head unit and lay it in the backseat while I figured out where to put the US Spec wires and box. All the connectors are specific to their female mate, so it is rather brainless to put it all back together again despite having 300 wires.
4. Mine is connected to a XM radio box under the carpet, near the passengers left foot. So, I used a mini-to-RCA connector between my XM and the US Spec unit, and stuck the US Spec unit right next to the XM (just further forward toward the fire wall). Used double sided tape rather than screws for the time being.
5. The area under the radio and dash is very crowded, so to route the wires between all the units (US Spec to Radio, XM to Head Unit, US Spec to iPod) I used a stretched coat hanger and simply used pliers to crimp the coat hanger around the end of the wire, and snaked it through. Worked like a charm.
6. My XM Head unit is attached to the a the front of my ashtray and fits perfectly in that spot once the handle to the ashtray was taken off. Makes for a nice steady mount, with the flexibility to slide it in and out for access behind the XM.
7. With my XM Commander MT being in that position, I brought the cable for the iPod from the US Spec unit through the dash and out to the center counsole right under the ashtray. So, it basically comes out under my XM Head unit and in a perfect spot for me to throw my iPod into the small, cigarette shaped coin bin just in front of the ashtray. Perfect!!
8. Benefits to using that part of the dash are.. it is descrete and you can always get behind it by sliding the ashtray in and out. Seems to be polished and didn't cause me to hard-mount anything or drill through the dash. When I sell the truck, I can put the handle back on the ashtray, and nobody would ever know it was used to hold a XM head unit
9. Finally, I moved my external XM antenna to the surface of black plastic piece that is just under the windshield wipers. It is exposed to the sky and because it is black, on black, nobody will ever notice it. Rooftop may be slightly better, but I didn't have to route the cable up the glass, and so far.. I have no gaps in the XM signal.
Things to still do.. I just got a 3rd gen iPod Nano and haven't hooked it up yet. So, when that is done I can tell if the Text interface on the US Spec unit is good or not... But the install, went very very well. Total time,,, 60mins including calling Crutchfield to find out that the XM unit has to be set up (from the menu screen) to be direct connect. Basically, I turned off the FM Modulation. You can chaulk that up to user error. If I did it again, it would take 30-40mins total.
Note.. You need a 3rd Gen iPod or higher. Really old ones don't work. My Mini didn't work so I gifted it to my wife. Also, make sure to use thread locker on the bolts that hold you Nav in. I used Medium. You don't want it falling out or bouncing loose. Finally, adjust the XM output volume so that it is matched to the volume on the FM Radio. That way you aren't constantly turning it up or down when you change "mode".
I don't have pics, but will post some soon.
Hope this helps.. So far,, I am very happy with the sound from the XM
