dude, take my advice closely. ive owned the 15 xxx, 3 jl12w3's, and 3 infinity perfect 10's.....
the xxx in the right box WILL undoubtably smoke the others....do 4 subs @ 28Hz. and call it a day. i promise you with that power (and itll take up to 1800 in this box), you WILL be shocked at how loud and looooooow it gets. the xxx isnt shit sealed. its made to be ported
and the SQ was the same from sealed to ported, exept ported it gets hella loud. stick with the xxx man, trust me