different body, maybe body posts and bumpers as well.
the only one that is really different is the axial dingo...as it has as shorter wheelbase than the others.

I like Imex dirt hawgs (pretty sure that's what they were called. Me and my friend both had them on trucks we drove in the snow.
http://www.youtube.com/watch?v=z7Do8HD9c-I Note that, to run 2.2 wheels on the scx10 chassis usually requires either trimming the body, or raising the suspension (longer shocks, or mounting stock shocks lower on the frame)