Wow. It must be brilliant to do this with a friend in another M5! And those are some really nice pics you have.
Agree on the Audi drivers. However I also thought the Austrian drivers in general had a tendency to obstruct. In Germany and Switzerland they tend to keep right and let you pass.
2014 Porsche 911 Turbo S
2015 Mercedes-Benz C300 Sport 4MATIC