I took a daytrip last week, running 600+ kilometer. The GTS performed flawlessly, though with about 200 km at WOT, she did drink a bit of oil (no, it's not an HPE). But I'm okay with that.
The following is a short video of the highest mountain road in the Eifel: the Hohe Acht. It's very close to the Nürburgring and one of the many nice roads in the Eifel.