yea was thinking of doing the same thing with my box. i have a side firing ports.. so the port wouldnt fire into the cabin, or the rear of the car either way i have them facing. figured i try firing in the cabin.. my box is a beast, so it should pretty much seal up the surrounding area.. some setups firing into the cabin get extremely loud (IE WALLS enclosures) but in trunks it varies on the sub box displacement, how much power your pushing, and if you get more "port bass" than actual sub bass. if you get more out of your port, and it fires in the cabin, youll most likely not be impressed and just go back to rear firing. it all depends on how well the trunk is sealed off after your turn them around. but go ahead and try it, see how u like it. and like mazda kid said, if your box doesnt fill up the trunk hole, stuff it what foam, blankets, pillows, whatever. because you get more sound after the bass reflects. so if theres no sealant around the box, it will reflect off of your front seats, windshield, etc, the waves will move back into your trunk and so forth... if not properly done right, the waves bouncing back will probably cancel out the waves moving forward (im on alot of xanax right now i hope this made any sense)