Interesting Radio Solution
 

From what I can tell, this gentleman modified the original stereo to allow for a phone to connect to and play music, plus added some amps. May be a good solution for some.

https://www.youtube.com/watch?v=wVc9svXp8Nc

I have been wanting to leave my original radio in the truck and then just build a small amp under the dash that runs to the speakers that I can jack my phone into. I just thought of something though, they should make bluetooth enabled 6 by 9's that are wired for 12 volts, that would make everything else moot. Oh well, have a look.

Re: Interesting Radio Solution
 

http://www.turnswitch.com/radio1.htm

Common conversion. It also converts just am radio to am/fm, can add blue tooth, usb port, and sub outputs.

Re: Interesting Radio Solution
 

Wow, I had no idea. Cool!