Is it the brushless rtr? I dont think the stock esc will handle 3s on either though. If ur racing, most tracks will only allow 2s lipos. So keep that in mind when you go buy new batteries. If you have the brushed motor, look into castle creations for a cheap high quality brushless. You can get the sidewinder sct 3800 system for $120 or you can get the sidewinder v2 system for $99. Ive seen the v2 in action and its pretty dang fast on 2s.
Sean