I've got 4 Berkline 13175 seats in my theater. I'm using an Elemental Designs A5s-300 subwoofer. I wanted to guild the lily and add transducers to my seats. Because of the smaller form factor of 13175s, I decided to go with the Buttkicker Mini in each of the seats. I originally ordered the BKA-300 amplifier from Guitammer. After waiting for about 4 months of the backorder, I purchased a Behringer 1200EPQ 1200watt amp and a Behringer PP400 preamp.
I mounted the Mini's to 3/4inch MDF board which, in turn, was mounted under the frame of each seat. I used the Buttkicker rubber isolators under each seat but this did not elevate the seat enough and the MDF was touching the carpet. I placed rubber furniture leg cups under the isolators which did the trick.
The Behringer amplier fans were extremely loud. I could hear them whirring away from inside my equipment closet where I can't hear all of the fans and hard drive spinning from my HTPC. That was a dealbreaker. Coincidentally, my backordered BKA-300 arrived the next day and I swapped this fan-less amp into the system.
With either amplifier, whenever the Buttkickers were dialed up to a level of good shaking, they emitted a very audible and annoying clackity-clack sound. The units seemed to be "bottoming out". If I dialed back the amplifier, I could eliminate the sound but the transducer would barely shake the seat.
I decided to trade up to the Buttkicker Advance, the medium sized transducer. These units fit under the seat like the Mini's. They are also rated to run on 75watts minimum, which, coincidently, is the maximum output per unit from the amplifier. What a difference! These things really shake and are totally silent. They are a nice but not absolutely necessary addition to my system. They enhance the immersive experience without being gimmicky.
One small complaint: the BKA-300 amplifier only has touch buttons for adjusting output without any kind of feedback. This makes it very difficult to make adjustments as you never really know your baseline. A panel of LED lights or a dial would be more useful to monitor output and make changes.