Hpi sprint or ofna ob4 international, I own (and crash) both, they've held up through some pretty impressive high speed collisions, thick plastics. The hpi is easy to get parts for the ob4 is impossible to find ANYTHING for, I can't even find another rolling chassis on line, the ob4 nitro version is waaay more prevalent. The suspension parts are shared between the nitro and electric versions, which is a tad bit easier to track down. That being said, I have noticed my more modern"race" oriented carbon fiber chassis are pretty tough too.