I've been running my Havoc with a 21.5 for a couple of race days and driving in my driveway. I haven't had any problems (knock on wood). This is my first jump into the world of brushless and I must say its great not worrying about all the maintenance that you have to do on brushed motors. When I pull the car off the track its barely warm. I'm running T/A and its working perfectly for me.