[Danglerb]

Maybe I have it wrong, but don't you want to tap into the factory wiring after the fader next to the driver seat? The signal to and from the passenger side amp is stereo, and most will prefer not to use a POT to set front rear balance since head units have it built in and include 4x channels of speaker level outputs. Use the pot and you only get half the head units power, 2 channels.

Doing the wiring "right" could be something to save for a major interior removal. I'd settle for a clean working install tapping into the existing wiring.

Check each of your speakers, carefully. During my PPI one of the items was radio does not work. 10 minutes with the manual a few weeks later and I found the front/rear fader set to all front, and the bass/treble to all bass. Front speakers had rotted surrounds, which means no bass, so I got no sound. Centering the controls (the old push and twist type) gave me ok sound, very treble in front, an sort of ok in rear.

When I pulled my door panels and saw the rotted surrounds I assumed the rears were in the same shape. Turns out they used a different surround material or something and were fine, but I found that out several hundred bucks later after paying to pull the rear seats, rear panels, and put in new speakers. If I had listened to each driver one at a time, using front/rear and left/right faders, I would have saved all that money and time.

I don't see a "lot" of difference in quality between the better major brands, but things often change from one year to the next. What they look like, and what features are supported is how I made my choice. I am sick of all push button radios, I wants some KNOBs. Other requirement were good MP3 support with a front USB port I can plug a thumb drive into, subwoofer out, non motorized door, and removable face.

Some of the head units do NOT match up well with the older look of the 928 console, space age chrome and flashing multicolor displays, yuck. Crutchfield is a good place to browse the models and features.