also touching on tires (i know we are wandering off the question here, but...) nitrogen filled tires is a good practice to have during track days as well, it fluctuates FAR less than regular air. during my last track meet in an an older 911, we had a monitoring system, ran nitrogen, and only fluctuated 2-4 psi. compared to 8-10 psi on slicks from fully cold to race warm.