Man look on ebay. There are so many subs on there. Kicker, Fosgate, M/A, etc. I run 2 Fosgate P2 12's in mine and have the box sitting right at the back of the trunk facing the rear and have been pleased with the sound. As for your 15's, I feel you on that. I was running 3 Punch 15's in mine at one point and had to build the box in the trunk. Talk about a pain.