Alright, so my buddy has two Kicker CVRs in a 4.5cubic foot ported enclosure tuned to 38hz (a little high, yeah, but it still sounds alright), getting 500watts RMS each. Would upgrading to a Fi woofer increase SPL and/or SQ in a noticeable manner, considering they will still be getting 500watts each, 1000watts total, and would be in the same enclosure as the CVRs are now (at least temporarily)? If so, what would be the best sub? In not a noob so no need to baby me, but im not an expert either so go easy xP