Regular cab truck owners Rockford Fosgate feels your pain. They've designed their Punch Stage 3 shallow enclosures so you don't have to suffer without good bass. And they build these boxes for strength and durability, with a computer-optimized design that uses medium-density fiberboard and thick carpeting.
Slim box, big bass
The P3S-1X8 sealed enclosure measures only 6-1/4" deep at its bottom, so it'll fit in the space behind many regular truck cab seats. It comes preloaded with a single 8" Punch Stage 3 Shallow dual voice coil subwoofer that'll handle up to 150 watts RMS. The enclosure's low 1-ohm total impedance means it'll drive your amp to its max just make sure you pair it with a 1-ohm stable amplifier.