Street Class is only for Redline, the other organizations have much different rules. Redline has very few events in the Midwest. Plan to do two events a year and travel to them, or plan to spend weeks on the road to make the entire season.

Another option would be NASA Time Trials. The Midwest region had a couple of events at Autobahn near Chicago this year, and all the events within driving distance of Chicago. I'm not sure what options the SCCA offers in timed events.