the oz does not have the SAME motor as the idmax. its very similar though, almost a knockoff. kinda dis-heartening but it hapens. still great speakers. i have two of the ME12.4's, and i have a pair of IDQ15's.
the IDQ15's have 600~800 RMS to them infinite baffle and they arent loud enough for me. im pretty sure they just want more power. ALMOST loud enough, but not quite.
the 12.4's were in ~3 cubes net, and had ~1500w from a american bass VFL150.1 in a ford ~95 tarus sho. they sounded real clean, kinda sounded like they wanted a smaller box size - but thats what was available for testing. they didnt get as loud as i would have liked - but again it was a pretty sealed up trunk and the box wasnt optimal for them IMO.
the idmax would sound similar to the OZ ME 12.4's and an IDQ has nothing to do with spl at all.
i think the right sub for you would be an IDmax or OZme. if you dont have enough power, dont worry about it for now. get it, play with it, and if you decide thats the case, then sell what you have and buy something bigger //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
good luck man.