i had installed some 22" (4) in the back of a vw sharraco (spelling?) back in the day, they were from concert cabinets, i think they need 8 cubs per sub - all i know i glued 2 sheets of 1" birch together and built the box out of that with 2x4 for bacing - real loud - sounded good from 50 feet away -
he had no backseat and the could not see out the back of the hatch - stupid - but fun