i built a unit that sits behind the seats, in the rear seat wells - it is a dual chamber unit, run in stereo - each chamber is .35 cu ft - each one has a JL Audio 8" 4ohm driver with a Profile 400 amp run bridged mono for each
i can still fit 2 cases of wind back there, and i get a back massage to boot
this shot is before i swapped out the drivers to the JL, but it looks the same
http://img.photobucket.com/albums/v481/flash968/IMG_1672sm.jpg