I did this when I was in Germany a year ago. Just a heads up to everyone, you can rent a car from as little as an hour to a full day. You can also reserve a specific car up to a month in advance -- Had I know this I would've rented an M3 before I made my trip. When I went there was still no M5 & the X5/X6 Ms hadn't be added to the On Demand lineup, the M3 was booked for a month straight. I settled for a 335i tho
Was incredible getting to drive a BMW on the autobahn & getting to open it up. It's that same reason why the On Demand program would be useless in the US, there's no where in this country where you can
legally do 100+
Highly recommend that anybody who goes to BMW Welt tries to get a chance in their "dream" BMW