Stock Traxxas Summit with NiMh batteries. I have one set of Traxxas 3000mah, and one set of Team Orion 4500mah. I’ve had the car for under a week, so I have not had so much practice yet. I have to say that the Summit by far exeeded my expectations, it is very powerful and have good acceleration. I can drive it anywhere. Nice running time too with 4500mah batteries.