I dont think its that bad... You get a little build up on on the side that the exhaust is on if you have a side exhaust. But as far as chassis goes you shouldn''t have any residue on the chassis unless your engine is leaking something horrible. The only time I get fuel residue inside my body is if my pit guy spills it. So like on a Tmaxx you shouldn''t have any mess at all unless your not taking care of the engine.