I would definitely like to know myself for future audio upgrades. I don't see why you couldn't find the pin-out and make your own, but it might require more than just a basic wiring diagram.
I was thinking this too, if you could buy the amp side connection then you could keep it truly plug n play without re-wiring anything on the car itself, the alternate option would be to find a burnt out amp (or cannibalize your existing amp) just for the "plug" on the inside of it, I did this when I relocated a climate control unit in another car but they were much more common in junkyards so the parts were available for a few dollars and I didn't have to feel bad about destroying something just for the female connector.Do you think it's possible to source the connector to the harness back there? it would have to mimic the amp connector. I've looked at the diagram floating around.
i would save time and get a good 6 or 8 channel amp, i know it wont have the power for my liking, but it should work for you guys.
how many still use the center and rear tweeters now?
if you get a 6 channel amp, you can do front 2 way active setup or a 3 way active setup.
are you guys still want to keep the stock radio but hook up to aftermarket amplifiers?
pac audio make something call amp pro
Toyota Advanced Amplifier Integration
looking at the price, i would just do a new radio and full rewire of the car. you either gain or lose the other speakers.
also why spend more money on factory limited feature? the new stuff have alot more updated features now.
Holy smokes that's pricey! Yeah, I'm going to not be lazy and wire everything properly.