How much air space / volume is in the driver's side rear compartment under the back seat of 1st Generation (through 2006) Tundra Double Cabs? I'm trying to decide between locating one or two 8" subs in there. I've seen the space listed at many different volumes while reading through searches. Has anyone measured that space and gotten an accurate reading? I did some fuzzy math and came up with .3125 cubic feet, but I think that's low because pretty much everyone else I've seen is listing a larger number for that space. I'll be getting the Polk MM840 sub(s) which require an ideal space of .35 per sub. I'm also trying to decide on, if I get two, whether I need to seal off the subs from each other with a center divider. Thoughts?