In my TT 300zx, I replaced the entire BOSE system and you do not have to re-wire the car. You can use the exsisting wires, you just need to figure out which ones to use. I can't remember exactly which color wires you use, but I'm sure someone on this board knows or you could try twinturbo.net

It wasn't that hard, just take out the BOSE crap and put in your new stuff. Got a dremmel?

Good luck!