ok,

I've been told that with the stock amps and head unit, you cannot replace the speakers because of the signal to the speakers. is that true? also, is there any way to run an amp off the signal to the rear speakers for subs. Like run high level inputs into a sub woofer amp. I also wanted to put a CD changer in my car. will it still work ok with the FM modulator?

 

I'm not 100% sure, but I have a strong suspicion that the Bose speakers have some weird resistance, and so you can't just replace them.

I know you can get line converters to turn amplified signal into line-level, and you could probably run this to an amp for subs.