Ben, I considered such an idea with my RX-7, and I actually COULD have gotten it ahead of the drive axle and met the requirements, but my engineer friends said no, not a good idea.

But, I would imagine that you could move it into the pass footwell area and still be within 12" of the original perimeter. Might help offset driver weight a bit. Of course, getting the car on the scales would be a prudent starting point. Also, any ballast you need can go up to the front of the footwell as well.