the rockford would probably be the most powerful it would do about 1650 watts @ 2 ohms. I've had experience w/ rockford amps and i like them the kicker would not be a bad choice either the hifonics is overrated but cheaper. Phoenix gold would be better then the hifonics but not as good as the kicker or rockford. definatley consider the jbl 1200.1 also like mr.brown said
Price is not really the issue. jbl do make some good amps but would the kicker or rf not be worth the price? As far as it goes it doesn't matter as long as I reach around 750RMS per sub with a clean power. Can't expect much sq out of a l7 but it is a downfire box so I think most speaker would sound a bit muddy.