ok so the amp...do i already have a stock amp in the car? if so, would i need a new one? i am guessing the sc3 and 400 have diff size subs right my boyfriend has a sc4 and his has way more base and pounds harder and mines 95 his is 92 so i am figuring i must have a 8 maybe and he has 10? i dont know im just guessing around that. So i know that i need something new back there whether it be the changer or the unit...i dont know how to tell...also i just want more power to the system so i am wanting to upgrade.....all the things you have are the factory right? so the only way they would make mine sound better is if mine was worn out or busted right? and i know they arent blown..