I wonder what you guys think about adding a FM modulator hard wired CD changer with mp3 capability. Looks like it's not as expensive as other MP3 solutions

 

FM doesn't really give you the best quality and if you're in an area with a lot of radio stations (like LA) you'll run into a lot of interference. To avoid interference, I think you should look into hardwiring AUX-IN or something similar.

Cassette tape adapter is a very cheap solution that works well.

 

I am thinking hard wired fm transmittor