All seasons are good enough for winter as long as it isn't cold, or snowing.

You don't note where you are in Canada. Vancouver isn't the same as Edmonton, for example. In Vancouver it is possible to just not venture out on the few days when it snows. Not so in Edmonton. And if you are in Quebec, I understand that you now need real winter tires by law.

Best bet is to have two sets of wheels, 18" for winter and whatever your favourite is for summer. Nothing beats real winter tires, and once you have them you won't go back. The vehicle has great performance designed in, so why compromise it with non-performance tires?

__________________
2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue