If you plan on just having fun driving outside on offroad, then you're probably better off with an offroad truck or buggy. I realize you might like the way something looks, but if driving it around isn't much fun. They will be setup to better handle the dirt and rocks. They will also be more durable.
People have converted their TT01s into Rally cars, but it requires modifications which might be too much for someone new.
What offroad brands are available to you? Traxxas, Losi/TLR, Associated, Kyosho?