The 530i is truly a great car. Although the RWD is the worst setup for winter driving conditions, it feels great for regular driving. I understand that Canada winters are quite bad. If you purchase a set of snow tires for the winter months, and the roads in your area are decently well-maintained during snow storms, you should be able to get around just fine.
I am assuming you have a front-wheel drive Passat....how do you get by, do you run all-season tires all-year-round, or do you have snow tires for the winter? If you can get through your winters with an FWD Passat with all-season tires, then you can definitely get through them with a RWD BMW with snow tires.