I think the sub is pointed down into the box space for accoustics. Kind of like the tubes you see for subwoofers, sub's are pretty much non directional but put them in an enclosed space and the sound becomes bigger. I'm no car stereo nerd though, if you got a teenager running around that's probably your best source for info  I wathced a tv show where they made a custom dash and interior for a custom, it looked pretty nice. My dash is out of the car right now and it has seen better days and I thought it might be an interesting alternative.