You should switch to the factory CEN part, you might be voiding your warranty if you run it in 2WD drive mode. Any R/C car will break parts if it hits something solid like a curb at high speed so I would just take it out somewhere open like a parking lot to get to know your car. You probably want to order a new gas tank from Cen as well because the epoxy might not fully seal the tank...an air leak from the tank could make the engine overheat and hard to tune.