loud subwoofer

I have two Cvr dvc 4 ohm subs. im running them at 1 ohm off of a Hifonics brutus brz 1200.1 amp. i want to upgrade. the Cvr are only 450 rms. i want some subs that hit harder, and deeper. what should i invest in. i have about 400 to blow on two subs. would i be better off selling my amp and...