Great thread. I took a chance on a set of Michelin 235/35-20 Pilot Sport A/S3+ – top-rated all season by far on Tire Rack's website, but I was concerned about their behavior in real snow, even with Michelin claiming better snow traction over the older A/S3. Well, as it turns out, I may have had nothing to worry about - what a revelation. Haven't driven the car yet in deep snow but on slushy roads, light snow, and generally crappy conditions (which are very plentiful in New Hampshire this time of year) these tires seem amazingly good. And their performance on dry pavement that is cold is just phenomenal. You can see from the attached picture they are obviously somewhat similar to the Pilot Sport 4S, but with obvious cross snipes and grooves to grab snow.
I still can't quite figure out what Tesla claims around improving cold weather issues around the frameless windows. The only thing that would really make a difference is if the system could sense freezing rain and lower the windows a quarter of an inch so you couldn't get locked out of your car. We had to turn the heat on for a couple of hours because even though I was able to open the driver side door, I couldn't shut it. Did some minor damage to the window frame in attempting to do so, although it's almost impossible to find unless you're looking for it. In any case the frameless windows mean that if you've got rain and then a subsequent freeze, you better make sure you lower the windows by a quarter of an inch before the freeze hits because otherwise you may not be getting in or out of your car without a whole lot of grief.
Overall though I'm extremely pleased with how the car behaves in slippery conditions. Not surprisingly, with electric drive, traction control can be much more finely graduated. The car just refuses to break traction and whatever traction is there, it's got. Absolutely incredible in light snow with these tires. We'll have to see how they do when serious weather hits – but this may not happen this winter since we're in Florida for all but two weeks of New England Winter crapola.