I wouldn't worry too much about pads or rotors for autox. If they are sufficient for the street, they'll be fine for your < 90 second run at speeds of 65mph or less.

If you were doing a Solo1 event and stopping from 100mph 3 times per 50 second lap in five lap sessions, I'd definitely recommend a high quality vented rotor and some race pads that are up to the task.