RE: not fair
Like some have mentioned, there are some advantages the truggy has over the MT and vice versa. Without going into technical details, the most obvious are that the truggy can corner better but the MT can soak up bumps easier while the truggy is bouncing around. Whether its fair or not is very subjective since ROAR has no official rule on MT and its all up to the track you raced. If you think it is unfair, just race somewhere else or get yourself a truggy or a MT that can maximize the system flaw. I have not personally seen or hear any truggy owner saying that its unfair to let the MT race in the same unlimited class (you figure out). Do not get me wrong as I am a owner of truggies and MTs as well and I used them on different tracks. If anyone thinks that just by having a truggy will make them have an edge over the MT, you are very wrong as I have seen MTs beating the crap out of some truggies as well. So in short, I would say get something that suite your driving style and that can possibly maximize the system to your advantage.
My humble 2 cents.