Cel, I think I just got your HP beat.
Check this out:http://www.funkywaves.net/catalog.cfm?item=fw_18_0
The TC LMS 5400 is a lot of car audio and home theater people are claiming is the best subwoofer driver (consumer-level) in the world, and the car audio guys are saying it smokes the JL 13W7, it's bigger, badder, and ALSO has 3 inches of linear excursion, and the driver alone is about 90 pounds.
If I had the arm strength the lift it...I'd take this sub. Although just like the HP, apparently they don't come in gloss finishes (too bad :\)