What up guys, I'm trying to figure out what enclosure to do for my 18 BTL. I can fit at most a 9 cuft net box in my bonneville's trunk. Is that enough for a proper 4th order bandpass? If a big *** ported will be better off, I'll just go with that instead. I only listen to rap/bass music with the sub on, so a pretty low tuning would be ideal. Power should be in the area of 4000 watts at most from a XXX-6500D.