A choice was made, and I put a set of the new Michelin Pilot Road 2 under the S.
In short, what a fantastic tire! They needed more time to scrub in than the Pilot Powers and they are very slippery when new, which was a bit unnervy.
Now, after this trip which according to my GPS lasted 7736km I am fully convinced of the capabilities of this tire. It has plenty grip, even in very hot temperatures and road surfaces. Even on high speed 130kph turns with the heads almost on the deck, they never even hinted of letting go. Instead it created nice little rolls of rubber on both wheels.

The times it did let go, caused by very slippery polished road surfaces, it did so slowly and without scaring me.
The tire stays nice and round and wear is very minimal. As said, I did 7736 on this trip, and there is still 2-3mm from the wear bars. Even after superslabbing home on the way back aka 1000km motorway, there is still no flat spot in the center of the rear tire.
These tires will last me at least 10,000km and I have not spared them in the mountains.
Will I get them again? That depends. For another big trip like this, in a heartbeat. For normal riding? No. They have more than enough grip, but they are still a touring tire. Which means the carcass is more flat for added stability, but also causing slower turn-in. Personally, I prefer the quick turn-in and twitchyness of true sports tires.
My perfect tire? The MPR2 with the shape of a sports tire.