I currently have a 96 taurus lx with premium sound and a factory 6 disc changer. I also have the integrated auto climate control, so changing the head unit is not an option for me. The stock jbl speakers are crap, so I replaced teh front and back speakers with Polk Audio EX572a's. I also replaced the tweeters with Polk Ex3500. So far I have paid about $180 for the six speakers and the wiring plugs to go into the stock harness. The sound is pretty decent, but the stock jbl woofer isnt clear enough to keep up with the good sound of the remaining 6 speakers. My sound also distorts when I take it to higher volume levels. I think this is expected when I am running off the stock amp. So now, I am thinking of throwing in a 5 channel amp in the car with an 8" polk sub. I chose 8" because I am looking for a more musical sub, rather than all thump. As for the amp, I found this one on crutchfield http://www.crutchfield.com/cgi-bin/S-NoMf8yvK2XB/ProdView.asp?s=1&c=3&g=120&I=158XM1805&o=m&a=0 It's a sony ES amp and it is last year's model. I think I can knock down the price if I do some seaching, but that is the absolute maximum i want to spend for an amp. I plan to run the amp at 4 ohms on all 5 channels. I'll probably go to circuit city to have them install the amp and sub and I wont be stingy on the wire. Does anyone have any suggestions or comments. Am I going in the right direction or am I far off for a system with pretty decent sound? I am sorta partial to polk and sony because I own several products from those companies and I am satisfied with their performance.