What Amp do you suggest?

Although the M2000 will give you about 800 watts RMS power more than the PDX, the M12 will be much more efficient, and obviously it has a much smaller footprint. I like the PDX series amps, and personally find Alpines Vpower amps to be 'power hogs' and not incredibly efficient. Those are both great amps, but I think honestly, the M2000 would be overkill on those subs. I would go with the M12, or a JL 1000/1. The JL amp is the best amp out there in my opinion. 1000 watts regardless of what impedance you're running (just like PDX), tons of controls to fine tune how your sub plays frequencies, and quality signature to the JL line. You will have much more control over your sub with that amp, as you can select the bass boost frequency, the amplitude of the boost, a selectable 24db slope, and even the Q bandwidth. The M12 is my second favorite amp. Don't touch Hifonics, they are nowhere near as good as either Alpine or JL. HOpe this helps.