I just got a 12w7 and put it in a slot ported box tuned to 32hz. Gross volume is 2.25, net is 1.75. It is fully braced with a double thick front baffle. I am powering it with a Phoenix Gold Xenon 600.1 with a birth sheet that says 816 watts. It does not get as loud as I thought, nor does it sounds as tight as I thought. Is the amp holding it back? If it helps, the car is an e46 BMW 3 series with no trunk pass thru and a very sealed trunk. Let me know if you think more power is key. Factory 120 amp alternator and battery, 0 gauge power wire to d block, 4 gauge to amps.