Then I have an Apple 40 pin extension cord that runs from the center console, up through my dash. Inside the dash I have an official Apple 40 pin to Thunderbolt adapter. I have that part sticking out of my dash in a cosmetically pleasing way right below my ProClip phone mount. I ...
I would recommend buying a high quality 1/8" stereo patch cord (yes, this is the same kind of plug you find on 99% of portable audio devices/headphones) and running that from inside your radio to your alternative sound source. I'm using a 6ft gold plated patch cable from radio shack....