FWIW...I can't say that I know all the ins and outs of all the subwoofers available these days. but, I do know that most conveniently available subs have thin walls, and sound like [insert favorite rude word here], as demonstrated by the way the sound in the store (or in some [again...]'s cars).
I also know that the subs I might want to buy have slightly more solid walls, are overpriced, and are not in my budget.
BUT, I know that my sandbox is beyond what I had imagined, so, I'm a happy camper.
My only error is that I didn't get a long enough sub wire (soon to be corrected).
Another thing... If you put 50+ pounds of sand into your sub...
verily thine subwoofer will much weight now have.
it's a minor detail
(oh, yeah, you can hear all the minor details too)