Brandon:
The Novak 13.5 BL motor is pretty close to a stock motor. It has much more torque, but not much top end (RPM). In onroad the lap times between a 13.5 and a good brushed are pretty close. BL is better on a tighter track due to the torque, brushed better on bigger... This might give BL a *slight* advantage in stock truck due to the torque...
However, Slim does not care if you run the BL 13.5 in stock. As long as you're not winning, it doesn't seem to be a problem.
As far as lipos, the same goes for stock. As long as you're not winning, it doesn't seem to be a problem. In mod, anything goes and Lipos & BL are both completely legal.