Here are my opinions. Until you swap out all 6 speakers and the sub and put an amp in, you won't get that much better sound quality. If you are using the original setup, you are just replacing 2 ohm speakers using the same wiring to your 2-ohm original system. You need to get 4-ohm speakers, get an amp, and use a PAC. If replacing all 7 speakers, get a 4-chan amp and put your sub on it's own channel with a remote control knob for controlling the sub.