I've had some great help from a couple of members here and I've read through nearly all the threads, but I'm still not very clear on one thing;

I have a 1996 SR5 with a tape deck, 51706 model. I want to swap in a double DIN unit to use a PIE aux adapter with.

So far, I found that there are two kinds of HUs - one with the amp built in, and one without. Today I discovered the plugs are slightly different, too. The CD changer plug remains the same but the other harness plug, not so. Can someone tell me which I need of these two, please, bearing in mind what's sitting in my dash right now. I'm inclined to think I need the a unit with a plug like in the second photo, but I can't be sure...



or

 

I just went through this with my '02. It had the external amp setup and the headunit itself looked similar your bottom picture on the back. This did NOT work with a DICE unit. (I don't know how the Pie wiring looks)
I ended up with a Scion Pioneer unit that had connectors more like your top picture and it works correctly without modifying any connectors or wires.

 

Here are a bunch more connector photos with pinouts. Even though they are from the Supra forum, I believe this is still valid info:

http://www.supraforums.com/forum/sho...ht=stereo+wire

Here is a pic of my 98 4RnR ltd HU. It has the 15pin external amp connector: