sorry. scale spec 21.5, hpi d compound tires, protoform zl1 camaro. gear diff is 3000 wt oil. im just thinking that ill try the gear diff in the front. if it makes a difference ill keep it that way. so far i can walk away from the field but i want just that little bit more. last weekend the spur gear nut came loose on me 5 laps in and i was walkin away. ended up walking away in shame. lol.