As for the tyres, I ran the kit SC10 tyres last year as Mark stated and they were "more than enough" everywhere on the track, my truck certianly never felt like it was ever "wanting" more grip.
Motors, as per Mark and Hog, why limit them? The buggy classes are open and so should SC be in my opinion. It will still be the same drivers there or therabouts at the end of the event regardless and it will prevent the boosted stock situation people refer to also.
As for Richs "suggested rule" about taking me out each lap, I fully agree, as long as the I can have him off too
(even if that does mean cutting the track to get him)
.
I propose that the new 2011 national champion starts every heat with a 1 lap penalty to start with (to give the rest of us a chance)