Wow, that's pretty snazy. It looks like they did manage to squeeze an 8 into the driver's cubby. I wonder if they've got an enclosure made for the driver's side as well. I can't imaging paying for those JL speakers and just leaving it free air, but there is not a lot of space for an encloser in there. I am a little curious about his enclosure volume. Sometimes you have to trade optimum efficiency for whatever fits, but I'd be surprised if that passenger side box is any bigger than .75 cubic feet. That's about as small as you want to go for an 8" sub. Even if you wanted to use a 6" sub on the driver side, making an enclosure big enough to sound good might be pretty difficult, and I don't think you'ld be happy with a 6" free air sub. I know I wouldn't. I just made a mounting plate without the box. Doesn't look too difficult to put together though. Just get out the tape measure or mom's sewing tape. That may actually be easier than trying to seal up the existing space. I'll measer it out this weekend when I pull the carpet and share my findings if you like.