Uh....2650Kv on 4s is way too much. Insane power, but not controllable in a track setting. Not to mention unwanted heat and smaller gearing range available. Ask anyone @ your local track, and they'll tell 1900Kv is plenty for any situation. Lower Kv = more torque, less speed, higher Kv = more speed and less torque. 2650Kv on 3s would be a good setup as well.