Buttkicker in a car?

Question - Has anyone heard of installing Buttkickers  in their car instead of, or in addition to, a subwoofer? I have them for my home theater and they are fantastic; I was looking at their site and noticed they have products for car applications as well as home. Im really curious about this as I am getting a small convertible soon that doesnt have room for bulky sub enclosures. Plus, with the top down, theres only so much audio quality you can get and Im more into feeling the bass than hearing a ton of it. As much as I love loud music, Im not that into having/needing people hear me thumping from 5 blocks away; I just want to have a solid sounding, reasonably priced system in a convertible application and I think the BK'ers may solve a lot of my problems.

thanks