Actually the difference is 2wd and 4wd. Stadium trucks are 2 wheel-drive any scale, it comes from the 1:1 racing world, they have an off-road class of trucks, that are rear wheel drive and they do call them stadium trucks. And yes they do look kinda like our RC trucks. Truggies are 4wd, and it doesn't matter the scale they do make 1/10 scale truggies or smaller, though 1/8 scale is the most popular size, and the term truggy is an RC only term.

Oh and as far as the guy saying truggies handle better, I'd beg to differ. My T4 handles any track just as well as any 1/8 scale can, it just takes more skill with a 2wd is all, there more prone to spinning out.