I recently got my Tempests installed, ported tuned to 32 hz w/ 6.5 cubes and 350w to each. I have the subs / ports facing the front of my van now. As it is, it gets pretty frickin' loud, but I was told that I could gain a little SPL by facing the subs towards the gate. Would there be a very noticeable difference if I did this? Oh yeah, and I know you guys hate to answer questions like this...but...could you give me a rough estimate of what kinda #s do you think I'd be hitting just playing tones in the 32-40hz range w/o burping or anything, on a new TL mic on the dash (No, I don't have any place I can get metered locally). By the way, the van is an '88 Grand Caravan SE.
Refs: 96civ, desertheat, baseballer1100, LowEndTheory, Belunt