When I bought my viper there was already a sound system installed. It came with two mounted alpine amps in the trunk and the factory subwoofers had been replaced with two alpine speakers. The radio is a Panasonic disk player with a small video screen that I programed to show short clips of Formula 1 racing. Pretty neat, BUT, since my Cats have been removed I have to crank it really loud to hear it. Also when I turn the bass up the speakers make the car rattle. So I don't turn it on very much. I've even thought about just transfering the system to my Boxster so I can enjoy it. Anyways, that would be like at least a 10-15 pound(2amps, 2 speakers, and a radio) reduction in weight. Hmmm? Maybe I should of got an ACR!?