i molded these boxes to fit in small compartments behind both seats. in the later models toyota put their factory subwoofer in here. mine was just a storage compartment
the mold was made of fiberglass and then i made the walls out of concrete. it was a 70-30 mix of recyled styrafoam pellets and mortar mix with equal parts mortar and coarse sand. a latex bonding agent called moose milk was added to hold it all together.
these boxes were built specifically for the Image Dynamics IDQ 8" midbass and the IDQ 52 midbass drivers. the 8" has approx .28 cf of airspace and the 5" has a small sealed compartment about .02 cf.
for the baffle i used 3/4" MDF and then made 1" mounting rings for the 8's and 1/2" rings for the 5's. then everything was sealed and screwed down and about a gallon of bondo was slapped on top. after a ton of sanding i used a spray on filler, sanded that with 600, then buffed it out with a 2 step compound system. the paint i used was just plasti-kote engine enamel #203 black and about 5 coats of enamel clear coat. the paint was buffed out after each coat, to give it some depth.