Ok im new to this rc car thing and my girlfriend bout me a sprint 2 drift sport for xmas. She knew i wanted a drift car and knew nothing about these rc cars so i was happy she got something i actually wanted. but heres the question the motor it came with is a 15t.... i dont know what it means (15t) and later on if i want to change it what should i go with and also what else should i change (besides tires i know this) to make it an ultimate drifter?