Originally Posted by SouthArk370Z

The main problem you will have if you keep the Bose is that it uses a lot of non-standard parts - it's designed as a complete system, not mix-and-match parts. This can cause problems (eg, impedance mismatches) when you start adding in more conventional amps, speakers, eq, &c.

As far as specific brand/model recommendations, if you stick with the major brands, it's hard to go wrong. I like Tadpole's advice - let your ears be your guide. Keep in mind that it will not sound the same if you are not listening in a Z, but you should be able to get a good idea of which components sound best to your ears. Nowadays you can get good sound in a car without spending big bucks.