ummm we switched out from kicker CVX's to the DC lvl 4's with lvl 5 upgrades, the difference is night and day, even though we kept the amp at 2 ohm (1500rms) for both subs it's louder than the CVX's and it's tuned lower on the gains and the bass boost is off, with the CVX's the gains were at 3/4 with bass boost at 1/4, the previous guy that tuned it didn't know what he was doing. with the DC's we left the amp at a bit less than half, bass boost off, and it hurts inside. the quarter panels flex like crazy when its hot outside, i'll try to get a video up of it this afternoon as i'm in the middle of class right now. they sound much cleaner and louder than the CVX's too, they don't get muddy like the CVX's do at high volume like most people say, which is true imo.