so you need like 3krms to get these things going. Look in to a sundown 3000D or a crunch 3000D even a kicker 2500.1 would get hese things moving, you say you have a dielsel audio amp, never heard of it. However those dual KX1200.1 strapped will make enough power if you have the electrical system to back it up.
Hopefully they get a loud as you want. though I would not pu two in boxes that are too small, you will be sounding a lot better if you just do one with propper airspace and power.
Though if you can build your own box this should not be a problem, what would be a probelm is putting MA audio subs in prefab enclosures,
pound those woofers for while and then get some real subs. Like I said, hopefully it will get as loud as you want.