Good write up, it brings back good memories of when I put mine in. You probably answered tons of questions for people and the pics are a huge help.
Dont sweat over not soldering, those crimps are fine if you dont know how to solder.
For mounting up your new 8120, you can also remove the factory metal brackets off the Tundra radio and use that to mount up your 8120. Its fits right on and is more of a solid fit than the cheap plastic mounts that came with the Metra.
My 80g iPod plays video on my 8120 just fine, as well as my new Nano. My iPhone works just fine with it as well. When you first plug in an iPhone to the 8120 it will say something about not being compatible with it, but just hit "close" and it recognizes it. Unlike the iPod, the iPhone still allows you control from the phone when connected, not just the 8120. I can use all my apps and they play thru the 8120. I listen to Pandora and AOL Radio all the time. Internet radio in the car is pretty cool.
Again, nice report.