agc

All,

I am thinking of upgrading part of my system. I wanted to change the speakers (same size just a better brand), sub and amp in mmy car; I don't want to change the head unit because I use my car as a daily driver and don't want to worry about break-ins. What do you guys think, will this make a difference in sound quality. Also want brand speakers, sub and amp do we have in the car; I know that the head unit is a Pioneer but was not sure about everything else.

Thanks