need help guys ..i cant decide what to get ...here is a little info,i have a trans am and the box i going to get that fits the rear well it has 1.92 cubic feet per side ...i was going to go with 2 15" or 2 12" ....the amp i am going to use is a sundown 1500d the 2-12" i was looking at are FI SSD or FI Q and the 2-15"are fi ssd or fi q...its a sealed box ....for that amount of air space (1.92cu ft per side) what would give me the best bass sound...thanks