There was a review in the most recent R/C Car Action on the Novak Brushless SS system. I'm not sure what gearing they used but the car just passed 41 mph in a tc3. And it ran for 10:22 on a GP3300 pack. Of course that was on a oval track so if you run it on a road course your run time will drop some. If you plan to run your car for the full battary run time and you have an RS4 Rally I would seriously reccomend not using the inside chassis cover. If you do then cut a decent size hole in it to allow good cooling. It said the avg. temp for the system was around 200 degrees farenheit (spelling?). That seem's pretty hot for me. I don't think the speedo got that hot, but I think that was the temp. for the motor and battary or something. Check out www.rccaraction.com
for more info, I'm sure there's some on there. Hope this helps!