Well right now I have two Type R 12's in a 5 net cube box. I'm looking to upgrade to a set of 15's. THe biggest box I can get would be 14 H X 32w x 30 deep. That gives me 6.288 net cubes before driver displacement. WHat two 15's would work good in my application ? Budget is $400 total for both subs Amp does 1200 Rms @ 1ohm Want a pair of 15's that has about the same or better Sq than my R's and gets louder.