start of with the 14 pinion. Maybe if the esc is sensored you might go to timing it.
But I`v driven the car on the Mach demo day (its on youtube by the way) and the car was on par with the suspensioned cars. Thomas was kind enough to put a 16 pinion on the motor though which had more speed. Car drove really good and I had good fun. Motor didn`t get hot or anything.