Sorry for bumping this one again :-)
If time permits IŽll be putting on some side skirts before summer, this I can admit is for the visual appearance. I'm considering adding a few layer of carbon fiber over the rocker panels before adding the side skirts, to add a bit of extra strength.. Would this be totally meaningless?
Another thing that I might try later would be to fill in the open parts of the floor with panels of carbon/divinycell and epoxy-glue it in. If they fit it should add some torsional stability, at least that's my experience from working with speed boats.
Well well, as long as I'm having fun..