I've done both at that event, but not in the same year :-)
At typical bmwcca schools that don't involve a race, though, you'll find a lot of the racers there instructing.
Look, no one's saying there aren't fast/skilled audi drivers, or that you won't find audi instructors with racing experience. It's just a question of critical mass -- that's all.
1988 BMW M3 #110 (NASA GTS2, BMWCCA JS)
2003 Expedition tow rig
1994 BMW 318i (commuter)
ex:
Audi Coupe Quattro
Porsche 911sc RoW
Honda CRX Si (x2)
1988 BMW M3
1988 BMW 325is
1991 Mazda Miata
1964 Dodge Dart - check out the rally blog
http://cars.g93.net