position of subbox in suv

[lasvegash2]

i am installiing a single 12" sub/box combo(jl audio) and was wondering how you guys are facing the sub...towards the backseat or towards to rear window. i listen to all types of music and i am looking for the best sound quality. i have done it both ways and it seems that if i face it towards the rear window, the bass seems louder but if i face it towards the backseat, it seems deeper. i am not a audio expert so any input would help me out. thanks in advance.