I've been running a pair of (400w rms) kicker comp vr 12's on my rp2k. I have been looking to upgrade subs ever since, in order to use its available power. I'm about to order a pair of American bass xr 12d4's that are rated around 1000rms. Are the upgraded subs really gonna boost my spl noticeably? Won't most of the now used power be lost in the motor and suspension? These are the things that go through my mind. Thanks for the feedback!