Well, there is that FAST racing class. I believe one of the big block mustangs is down to the 9s. Although i don't know how stock the interior has to be.
4) Correct Appearing. Everything not specified otherwise must be correct appearing. “Correct appearing” and “appearing correct” means: upon a cursory visual inspection by someone reasonably familiar with the year, make and model claimed, it looks like a correct* part.
1.08 Interior seating, trim, and materials must appear correct.
1.09 Aftermarket tachs and gauges are allowed if mounted on the steering column or under the dash.