Tires are definitely #1 for snow and ice performance. AWD is #2 and AWD systems are NOT all equal..not remotely. The Model 3 setup of dual motors with open front and rear diffs seems pretty good, better than many ICE AWD systems, not as good as the best ones (from a pure traction standpoint). Its rear bias is not ideal for snow and ice traction in my opinion, but at least in Track Mode you can adjust the power delivery balance, dial back Stability Control, and dial down regen all at the same time. I haven't driven my M3P in the snow yet but that's my plan - 50/50 power delivery (or even 60/40 front biased), Stability Assist all the way down, and regen all the way down/off. I'll play around with different settings and see what feels best to me of course.
I would normally not want Traction Control for snow and ice driving. If my right foot requests wheel spin I want the car to allow it. The one exception is with open diffs, like the Model 3 has, then TC's braking of individual wheels to limit slip is probably useful. That is all I might ever want from TC in the snow and ice though, and it's definitely inferior to having good limited slip diffs.
Real limited slip diffs can be great (and they're not at all created equal either, there are many different kinds with widely varying behavior), *but* any good ones would probably kill efficiency in an EV. The EV solution should be quad motors (per-wheel motors). Can't wait for small, sporty 4 door EVs with quad motors to become a reality.
AWD will help you get going, but it doesn't help with turning, or breaking (all modern cars break with all 4 tires). Braking and turning are the most important dynamics if you want to avoid an accident.
@ev_go123 I mostly disagree with this. AWD helps very much for changing and maintaining a car's direction in deep snow. And while AWD doesn't directly help with stopping, sometimes the added maneuverability helps to go around an obstacle without having to stop for it.
For actual stopping performance, besides the tires which are critical, the car's ABS and brake force distribution can make or break snow and ice stopping performance. My first AWD car had a terrible ABS system that kicked in way too aggressively, well before the tires all ran out of grip, and the brake balance never felt great either. Stopping distances were bad even with good tires, it couldn't put their stopping traction to use. My next AWD car had a fantastic ABS+EBD system and it was night-and-day better for braking. (It also had a much better and more advanced AWD system, and that too was very noticeably better for acceleration and turning under power.)
I haven't driven my Model 3 in the snow yet, but I've been very happy with its ABS and EBD (brake force distribution) performance in the dry and wet so far, including one complete panic stop on a highway (from full highway speed). It feels like those systems are tuned pretty well, though of course dry and wet are a far cry from the really slippery stuff, so I don't want to make any promises for snow and ice performance just yet. Hopefully next winter for me!
Tires are still the most critical aspect by far of course, but it's not an either/or thing if you care about snow performance. Snow tires, a good AWD system, and good ABS+EBD are a great combination to have. And let's not forget ground clearance. Model 3 is passable there, not great, not the worst. Some car makes get this right and maintain decent ground clearance in their sporty AWD cars (e.g. Subaru), and some do not (e.g. Audi). I'm actually tempted to lift my M3P slightly when I put my coilovers on, at least to M3LR height, and maybe slightly higher.