I am no stranger to making my own custom sub boxes. For example here are the custom molded sub boxes I made for my xB which sat under the seats of the xB and held 12" subs, having proper air space for the models. I used this set up to win SQL competitions ...

So yesterday as I was dismantling the interior of the B2200, I noticed the two large tubs I have access to in the back of the cab. The one behind the passenger seat and the cubby storage where all the jack equipment is behind the drivers seat. Have you guys ever seen anyone use these spaces to make sub tubs out of?

I see massive potential for a pair of 8" subs and still keeping a majority of the floor completely useful? I may have to start a new thread someday as I build a custom enclosure in there .. Muahahaha