If you're interested in "touring" laps on the track at the Autobahn...
(No helmet or "legal" roll bar needed.)
CAROC - Chicago Alpha Romeo Owners Club has a spring event May 6th & 7th.
They're looking for volunteer corner workers. They'll let you do the Touring session on the track in your car in exchange. OR you can skip volunteering and pay the $50 fee. I don't know their speed limit. It's not a full speed session. BUT you don't need a "legal" roll bar or a helmet.
It's a fun way to get on the track and practice your "line" around the track.
Contact them through their website:
www.caroc.com