I remember seeing an Engineering Explained video where he did braking tests on summer tires and studless winter tires at 25F. The summer tires actually stopped the car significantly faster. I believe performance winters split the difference and perform much better in the cold-dry than a studless...
I have a GT PP as well. I ran 3 winters on Pirelli Sottozero 3's and think you'd get great use out of them. Really good grip in the cold and dry, and seemed great in the rain. Acceleration seemed to be on par with a FWD on all-seasons, but having driven that setup before, I have never once felt...