Any ideas for installing one or two buttkickers (tactile transducers)

I am thinking of going with one of them instead of a subwoofer to get a nice bass sensation from the music. To get the idea of what these do, these I believe are original creations: (link removed, please google "buttkicker") but I have had some nice experience with similar transducers from here:
(I am not allowed to post links yet, please google "BAS PUMP III 8 OHM", the first result is it.)


They seem much smaller (must be easier to fit in the car), are cheap and work great.

What would be the good place to put these in the car? Did anyone had similar experience?
Right now my idea is to get 2 carefully designed sheets of steel (perhaps ~3mm thick) with some holes which can be screwed under the front seats, and attach the transducers to these sheets.
The sheets would be screwed to the "bases" of seats, the two (per seat) black long tracks on which the seats roll when they are moved back and forth.

The only good place to put the amplifier is only under the seats as well it seems, because otherwise the wires have to go first from the front speakers all the way to the rear of the car, and then back to the seats again... However with the sheets and transducers installed there don't seem to be much place left.

Also do you think the position of transducers in the car will be ok? Front seats are not exactly in the middle of the frame, but since they will be attached hard to it, I guess the frame will get enough of the vibration anyway, and front seats will get most effect which is nice. There is no structural danger in exposing the frame of the car and seats especially to these kind of vibration, right? I mean, the car vibrates all the time when it drives anyway...

Also there is a black box under the right seat, it looks like an amplifier for the built-in sound system. Is it possible that this amplifier already holds enough additional power so that no extra amplifier is needed? The power rating on the transducers is only max 80W per unit, so we are not talking about a 1000W extra for a big subwoofer or anything like that...

Any input or information is appreciated.