3 subs makes it tricky either way. With dual 4's you're either going to have to wire them for 2.67 ohms, and get an amp that's 1500-2kw at 2 ohms (which would give you something around rated power at 2.67 ohms), or find one of the rare amps that's 1500w+ at 1/2 ohm and wire them for .67.
With dual 2's you'd have the option of 1.33 ohms which would work well with a 1 ohm stable amp, and it seems to me that would be the more cost effective route. The HF bxi1610d would do a good job for less than $300.
I agree 100% with optidriven, I'd swap for dual 2's. There are a tone of 1 ohm stable mono amps on the market. Can't comment on the new HF amps since they are different now, but are suppose to be much better than when maxxsonics owned them.
Maxx does still own HF. They just cut back a little on the chrome and lights and applied that cost toward circuit board upgrades. Claimed to produce rated power at 14.4v and very close to rated in the 13.8-14v range.