I did almost all of the above choices last summer. I would rank Nurburgring over Stelvio especially if coming from the north. I would also recommend any of the Swiss alpine passes over Stelvio just for ease of driving (less narrow) and the ability to do 3 or 4 in a row, only thing is the required Swiss vignette. As far as the insurance...drive on the right and don't be stupid. I reached higher speeds on the autobahn and didn't have the wife telling me to let her out...
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2018 M2- LBB, DCT, Moon, Exec, Apple- ED
2021 X6 x40i- BSM, Tacora, Msport, Exec, Lux Seat,
Park Assist, Red Sport Brakes -PCD