They were built to destroy JL's W7 series drivers, and they look like they will. Each one weighs over 50 lbs and has 4" of excursion. The 10" driver has more than twice the displacement of the typical 15" driver! I need to find out if these subs can be used in sealed enclosures. If so, I'll build an enclosure for my HT system using one of these subs. It should require a much smaller enclosure than a 15" driver, and it'll move a lot more air.
These really won't be good at all for home theatre. The FS of the 10" driver is around 40 hz which limits your output below the fs extremly. It won't go very loud at all with 82 dB sensitivity, and you'll never end up using all of that excursion it claims it has, and you'll end up wasting your money. These things are made for those crazy SPL freaks that play at those db drag competions. If you want to make a nice HT subwoofer go to partsexpress.com and look at their selection of speakers. also download a program like "speaker box designer" or "Winisd" and make a box using a subwoofer driver's t/s parameters, this will save you a ton of money and get you something good sounding.
also look at the Dayton Titanic MKIII 15" subwoofer from partsexpress.com. It's $50 more, but it will perform better then the tempest. they're also selling some Nice 1000 watt sub amps with built in parametric equalization so you won't need to buy a behringer feedback destroyer. Thats my 2 cents