Car Stereos: Factory Amplifier, sony xplod, cheap amps

Question
I replaced all four speakers and the cd-deck in my 2001 chevy impala with a Sony Xplod sound system bundle that is supposed to be better than my stock system but I seem to have lost some bass. Can I fix this by replacing the factory amp, or do i just have a bad set of speakers. Specs: 45x4 watts cd deck, Two 6 1/2in. 190 watts peak, and Two 6x9's 300 watts peak

Answer
Brian, If your car is equipped with a factory amp, you should replace it with a better one to compliment your new speakers.  As for the loss in bass, I would reinstall the factory radio and see if that makes a difference.  Factory sound systems have cheap speakers, cheap wires, and cheap amps, but they have some of the best radios made by the top manufacturers.  If the factory radio proves to have the missing bass, I would suggest looking at an Alpine aftermarket radio to replace it with.  Hope this helps, Scott