unfortunatly with the TL01s many many gears anything more than a stock type motor is too much. I would say the 13.5 would be ok and possibly the 10.5 but thats iffy. Your best bet would be to get the brushless system and plan on getting a new car if you want to race. If you just want to drift around the 13.5 should be ok just use the biggest gear you can fit on a TL01