Last guy I personally dealt with got a birth sheet with his orion that said 2750 watts or so, but I hate the fact that there's a fixed 25 hz SSF. The other choices do have an adjustable SSF i believe, id personally rule out ANY amp with a fixed SSF if I was using a ported hi-power setup... idk, maybe it's me?
If it was me, id buy a 2 CAB's and strap to 1/2 ohm... once my electrical was up to par I was having a great time killin my Evl-12's and the power was pretty high.
Idk what numbers power wise I was getting but I'd suspect if dynoed the pair was putting out around 4k.
That being said, just get a pair and run em at 1 ohm each and 3000+ ought to be enough... for $400 shipped it's a pair of amps thats hard to beat.
Im just nuthuggin here... I had good luck with mine.