Right now I have 2 10 " mtx 6000 ( model is 6104A) subs (250 w RMS / 500 Total ) both are single voice 4 ohm. In sealed enclosure each with about 1 cubic foot volume for each. I have them both hooked up to an MTX 6500D amp
12.5 VDC
2 Ohm Load 500 w x 1
4 Ohm Load 250 w x 1
14.4 VDC
2 Ohm Load 775 w x 1
4 Ohm Load 450 w x 1

The voltage going to the amp is around 13.75. And I'm running it at the 2 ohm load.

If I want to go louder, more punch from the subs. Can this amp power more powerfull subs? Any suggestions on whats the max I can get for this amp. Or get a more powerfull amp?

port them bitches first, see if spending a little on some MDF gets you what you want for way less than a couple new subs.

they look about even in terms of specs. I'd say for more bump, go with a slightly bigger amp. though if you want more, just go with better subs and amp altogether. ported is louder than sealed, so that may save you a couple hundred $$. a huge sheet of MDF board where I live is only $15 (I think it was about 40x80 inches)

49x97 at Home Depot will run you about $19-21 here, get it cut up to five cuts free so it fits in the car and be on your way home to make sawdust for a couple hours.

seriously though, if you have made up your mind and want something different, before you drop a couple hundred bucks do a few searches on here and PM a couple of the guys asking for help designing/getting specs for a ported box for your subs. just remember to give them as much info as you can to make it as easy as possible for them, they're doing the favor, and just compare costs. If you plan on spending $200 + dollars on subs, whats an extra $20-30 to build a box first.

I'm glad I did.