Sweden is a big country and the climate is nowhere close to that in Alaska if you live in the southern parts. I've run GT and other performance cars with R-spec tires, so that is not a problem.

The only thing that would stop me from mounting Cup 2s is if there was any danger damage (oil starvation, hubs or anything else), but I can't really see that. Especially since Porsche have been doing the rounds with the GTS on the new N-spec Corsa-tire from Pirelli.