One of my mates got a MTX-4 he ran the engine in on another car. Had the New MTX-4 never seen pavement starts it up puts it on the ground opens the throttle fully then the battery plug came out to the car went full speed down the main straight and smashed into the kerb and the chassis got bent in two places in front of and behind the battery pack area the front bent down and the back bent up. No one said anything to him for like 20mins . we almost saw come out his eyes and fair enought to. But he got the car fixed new chassis, tank , middle deck, front damper stay, front bulkheads (200 NZ$ about 140US i think). now he checks his plugs all the time .