Why? Last year I raced a couple of times at a track up north and they have a class like this with mixed buggies and truggies in it and it worked well. They did let SCT 4x4 in on occasion, but suggested mixing SCTs with the 1/8 scale was not a good idea as the 1/10 scale cars would get pushed around by the bigger truggies and buggies. I can see that experienced guys would not like this, but for the beginners (like me) I don't think it makes much difference.