I've gotten mixed claims on this and I want to put this to rest already. I want to know how much air space there is behind the seat of a crew cab so I have an idea if my subwoofer plans are going to be good or not. I need 1.5-2.0 cu. ft. total. Not sure if I'll be using 3/4" or 5/8" MDF. As of right now, the plan is not to use any bracing, so that won't take away from the air space. Also, what is the MAXIMUM depth so I know whether or not the subs I want to use will fit or not. THANK YOU.