I had a 4 channel amp installed on my 2004 compg. its an alpine 50W RMS per channel etc etc.. my front speakers are polk audio and my rears are kicker 6x9's. The amp powers those 4 up, and my factory monsoon amp was wired up so that it runs the tweeters in the front doors and the center speaker on the dash. I kept my stck headunit because i like the factory look. Overall the sound is incredible and the sub isn't even hooked up yet. Well worth the money. not many people get 4 channel amps installed but im glad i did.