At my last event there were two guys in the same car. The club made them run in different heats, and mentioned something about "cool down time." I think this means that there is a requirement that a car not be allowed to run, say, 8 times in the same heat, even with different drivers. Probably a safety precaution?
Anyway, as long as you both register, and run in different heats, well I see that all the time around here.
