I actually built the enclosure you have.
MEL! This cat scooped up all of Seth's equipment! The XXX he has is the one we took to Twin Falls! I personally blessed that sub, so it is guaranteed to be loud. Be careful how you wire it, I'd definitely test it with a multimeter, hooked up to the amp, on a tone, just to make sure everything is wired properly. Quad coils are weird to me. When I dropped my XXX in my horn (exact same enclosure as yours, but I got mine Line-X'd) one of the terminals got hemmed up on the sub cut out. SOoooo I ended up throwing 3000 watts to the one coil.
If I didn't live about 7 hours away from Bozeman and need a recone (again), I'd hit this show up.