Thanks for the "heads up" on this thread Chris, but unfortunately, I use the 'Buttkicker' amp to power one of my TC-12 OEM subs, not in the capacity that Tommy, I believe, is looking for with the Buttkicker transducer kits.
I would have to agree with some of the other posters here, though. A properly placed and calibrated sub that can get down to 20Hz (or come close) can produce a similar effect without the added expenditure. Of course, this would also depend on the size of the room it's being used in.
I think transducers like the Buttkicker kits and others help to enhance LFE for those that either can't listen at a loud volume or choose not to, but would still like to have the tactile effect they can produce.
If you've got the space and can listen at louder volumes (e.g., not restricted like an apartment, townhouse, etc.), a well built, strong performing sub can give you a similar effect without the additional cost... -TD