[Rick Lee]

I would rent a car. Nurburgring is nowhere near Stuttgart and I don't think there's a train anywhere near the Ring. I usually go to Germany every summer, but always rent a car, so I don't know if Uber or Lyft exist there. I doubt it. I would drive that whole route, some combination of Strasbourg, Paris, Stuttgart, Cologne. It will be faster than a train and, while gas is not cheap in either country and France has big tolls, it costs the same for two people as for one, whereas trains will be two tickets everywhere, you will be on a time table and then will have to schlep luggage and deal with taxis.