First production run LR RWD M3 owner in Ottawa here. I hail from Labrador West so I know how to deal with extreme cold, I've personally experienced -106 C (exposed skin freezes in minutes). Just last week, my family (in Labrador) just went through a bout of -45 C cold. So why all the background? Well I'm tired of reading/hearing all the comments that cold reduces range. Cold does NOT lessen the amount of electrons that are stored in a battery. Cold DOES inhibit the ability to discharge or charge, aka move electrons, for a battery. When a battery warms up or keeps warm, it'll work as normal with the same amount of electrons that you put into it. Of course, this has NOTHING do to with how you use (budget) those electrons. Obviously, some of those electrons may have to be used for heating instead of movement. This is the "perceived" range loss but it only applies if you don't thermally manage things. Remember thermal differential is the real culprit here. If you want a warm car/battery, full regen, and long range in cold weather it depends on your starting point and what you're powering.
Rule number one in cold (or hot) climate: When there's a high temperature differential, it's takes less time and energy KEEPING things warm (or cold) than warming (cooling) things. When the differential is not so much, it's a push. For me, I run the car's climate keeper both in summer (AC recirc) and winter (Heat recirc.) while parked at work. I hate a hot car or a cold car. When parked (no plugin), in summer (hot) I use 15-20% battery in a 8 hour period. In winter (cold) I use 25-30% battery in a 8 hour period. Of course, I start the day with my car being at optimal temperature and 90% charge (I use % energy instead of distance). With a 1 hour commute X 2 (to & from work), I get home with above 60% for summer and 40-50% for winter. In other words, I use ~10% in my commute in summer and ~20% for winter. This assumes thet my car is always at the right temperature (20-22 C) at start and I may have slight regen loss (winter only). Only on the really cold days (with windchill) that I might get the blue snowflake (not cold soaked though) and/or full regen loss but it'll get better on commute.
This is my experience for Ottawa, for a garage housed Model 3 with a moderate commute (mostly city driving). I find that my LR RWD exceeds my needs. A SR+ should easily have enough range given same assumptions.
Kaoru