[Exocer]

Soundsplinter makes a great driver, but I fear without proper dedicated EQ you won't have the large amount of output down low for HT you're looking for. If you're willing to buy something like a Behringer FBQ2496 you'd get some usable HT bass. IIRC your room is about 3400ft^3? thats still pretty tough for a single driver sealed sub to fill.

If you're open for going ported the SS driver makes a lot more sense. Since you seem set on the sealed box the Rythmik kit would be much simpler to get up and running since flat frequency response is literally already built in.