Well, I never cheated for my sons. They owned what they built. For my oldest son, who cut out his car with a coping saw and painted it with a brush (it looked like crap), he was ecstatic when he got second place. The winning car had about 12 coats of hand-rubbed lacquer (looked like a block of obsidian) and his dad machined the wheels in the machine shop at his workplace. His eyes were bugging out when he saw his son's car win by about a centimeter! Some kits are faster than others. Son's car was also underweight, so the guy running the event hot glued a washer on it. 🙄
As for graphite, that's still the go-to, though there is allegedly an oil that works better. I'll stick with graphite, personally.