This is the 6th Ex cab I've done like this, I have my own brackets for seat and seat belts to raise it 3" so its even with back window. This one I went into the side compartments to get extra .67 per side. The box under seat is 3.3 cu ft thats not including the wedge at bottom for down fire subs. Memphis tuned it at 36 hz. Made with 3/4 mdf, fiberglass and resin, and all area around was foamed. I'll post some picks later. Thanks