I just ordered a Soundstream SPLX 15 (new version). I have the old box that my PA MOFO 15 was in, 4.4 cu. ft. gross volume. It currently has two, 4"x12" aero ports, for a tuning of around 32Hz. Both Soundstream and PA recommend two, 4" aero ports for these subs but I have heard that I could possibly get port noise. Would I be ok for SPL with the two 4" aeros or is that not enough port area? A calculator I used recommends a MINIMUM of 40 sq. in. of port area for the SPLX but two 4" is just over 25 sq. in. and one 6" is 26 and some change. Anyone know what my best bet would be here? Thanks in advance everyone!