stereo help

I want to know what to look for in an aftermarket head unit as far as sound quality. What specs should I be looking at to determine if one HU will sound better than another. I have a 2002 Saturn L200 with a BOSS BV755B headunit and honestly it's done everything I've needed but I feel like I...

Ever since I got my Sony headunit which has a built in 45w amp I have been having problems with it shutting off when I crank up the volume to around 45-50 (50 is the max volume) and the bass hits. I have replaced my battery, alternator, checked my ground, and it still does it. I did however find...