This photo was discussed a while back on the S Reg - the problem with the tires isn't really whether they're slicks, treaded or their width. It's the soft rubber compound and the cold temperatures - any racing tire mounted on that car in cold temperature would turn hard as a rock. It's tough enough to get heat in these tires on a hot summer day and a dry track! Anybody with summer performance tires (i.e. Michelin Pilot Sports, etc.) on their 911 know that they are extremely dangerous on perfectly dry roads when the temperature dips below 35F or so. There's a video on YouTube of Mika Hakkinen taking his wife for a ride through the snow in the 2-seat McLaren F1 car with unstudded race tires - so it can be done!
