vdubvr6

Hey guys, I'm new to the ssa community and I just had a question about whether I would be better off with 2 12's (most likely fi q 12's ported and tuned low) or one really loud 15 (most likely a DC xl 15)..obviously ported.. Ok first of all, ill start with the basics..I drive a Volkswagen jetta so the most I can squeeze is 3.5-4 cu. ft...and for power I've got the audioque 2200d and a 220 ho alternator with 1 red top (starter battery) and the big 3 with 4 Ga...now given my trunk is relatively small..I would probably be better off with 3.5 cu. Ft. Recommended for the DC xl but..its taller and would most likely not have enough air space to bounce back off of my trunk lid or am I just totally over thinking all of this? I know I could make a box pretty short (13.5-14" high) for the q's so would that be a better fit or not? I've got the power for both systems but just unclear on the right application..thanks for your help!