Hey, I know this is an old thread, but I found out about auto-cross in Sioux falls only a year ago and have only made it for one event. Once I get my car I'm going to try and get my friend to cruise up there with me. He has a 2010 SS Camaro. Not sure if we'll run, but we'll for sure be enjoying the show. Also might have a friend who can bring a newer 335xi.
You still go to the events? See some pretty sweet rides there. A lot of newer evo's and vettes. The one time I went they had a new GT-R there as well, think it was the guys who put on the event. Seems like most of the cars are tuned by Excessive Auto.