A quick update: The Coupé got the promised inspection:
- new spark plugs
- oil change
- new thermostat
- new brake fluid
After that, I took it to my home (350 km highway drive), but I left the highway after 200 km and took side roads instead. What a blast, especially the engine! Smooth, not too loud, plenty of power. Although I drove quite relaxed, it already made me hungry for more. After the ride I got a nice surprise at the gas station: it averaged at 8.5 l/100 km. 
So when driven a bit more sporty, below 10 liters is definitely no problem.
During the weekend I drove it through the vineyards in Palatinate together with a colleague in his Z4 3.0 convertible. Very nice roads, nice weather, lots of fun. And I already noticed another advantage of the Coupé: My colleague has a severe sunburn after 4 hours of driving, but I am completely fine 
Next plans: wash the car (currently lots of pollen and dead insects) and give the leather seats and dashboard some love. Hopefully soon I’ll tour the northern Black Forest. More pictures to come!