Here’s my itinerary so far. After picking up car in Leipzig , we head to Munich for 2 nights. Maybe tour Austria while there. Then down to Lake Como for 2 nights. Drive into Switzerland… 2 nights in Lucern and 1 night in Zurich. Lastly drive through Black Forest on way to Sindelfingen to drop off car. I was thinking of going to Stuttgart factory before taking train up to Frankfurt airport. Do I need reservations for the factory tour? Or is it enough to just walk in and do self tour?