I just got a new ride and thought about putting a computer in it with a touch screen for movies, music, games, etc. I have an amd sempron 2200 with a 400 watt power supply, factory fm radio, and factory speakers. I was about to purchase the power inverter so i can use my cig adpapter for the computer power. Can I use a 300 watt inverter on a 400 watt computer power supply? It has built in sound so could I run the speaker out 1/8" cord to some kind of adpater or solder a new wire on for an RCA input on the amp? And can the head unit splice in with the RCA of the computer into the amp input? or does some amps have dual inputs? (havent purchased the amp yet) I would have to unhook the radio from each speaker I'm guessing and hook it directly to the amp -hopefully the radio has RCA out? Then rerun each speaker wire from the amp back to each speaker..Any suggestions?? Thanks -JC