either way, it will be good. i threw an M6 in my car the other day when i was at the shop just to see what it sounded like (the shop got some pre-fab ported boxes that were "supposed" to be made for the M6 specifically). it was a dual 4 ohm, so i ran it at 2 ohms off my 1200.1 which makes 600 watts @ 2 ohms, and wow, it was loud as hell, loader than my TDX in a sealed box running 1200watts. that M6 sub is impressive, and like all diamond subs, it wants power. if you are going sealed, you might just want to get that hifonics since it makes more power, but in a ported enclosure, i think the 600watt JBL should do the trick. (make you make a good ported box, cause this prefab thing i used for the M6 sucked, they didn't make it right, and it sounded like crap, but it got loud)