Hi for those of you who runs on asphault circuits with the sprint 2, how do you have your differential setup? Does anyone mess with it or just keeps it in stock form. Or does anyone have a writeup on running thicker weight oils or grease or whatever it is. Sorry I have the RTR version and Im trying my best to be able to keep up with the big boys. I figured this would be the best place for me to ask for setup tips.