Keep in mind that if the speakers are new there will be some break in time. They will be TIGHT out of the box. After a few hours they will start to loosen up. What ever you do make sure you give them plenty of clean power and build a good box. Those subs will rip a half a$$ box apart, literally. They have massive excursion. I would look to the older kicker zr line. Can be bought for a good price, tough as nails, can run low impedance and underrated. My zr 600 delivers 761w rms. I would also look at the ppi power class amps. I have two of these in my boat. Clean and underrated.