Anyways, I believe replacing your factory speakers with a quality set of aftermarket speakers is one of the best things you can do too inprove over all sound quality. I don't have alot of money, so I buy the best I can afford and save up for my audio equipment. Anyways, I highly recomend the Infinity Kappa speakers. They sound great !!!!! Price isn't all that high, well worth every penny I paid for them. I'd also recomend poweering them of a good 4-channel amp. The music really comes alive. If you plan on a sub, run the 4-channel amp for the main speakers on High Pass, and let the sub ( on a amp by itself ) handle all the lows. My car stereo isn't no competition system by any means, but sounds way better then what the factory put in the car. (See my sig for my system info)