If you are thinking about alloy rims, you could buy 17" rims and mount 215/55R17 Nokian WR which are V rated and an exact plus 1 conversion for your car. Also check www.carmodifier.ca for pricing on the Nokian WR. I drove the WR's predecessor the NRW, for several winters in Halifax and think all weather tires make good sense for urban commuting in the milder areas of Canada - especially if you can let the plows go first. 55 series WR's on alloy rims may even improve the handling but that probably isn't an issue for a family sedan.
Thats the second priority option for me and most likely will cost twice as much, then I have to dispose off the steel wheels and the spare.
Why would you have to ditch the spare if the outside diameter is the same? 
The most likely at the moment is the new Nokian WR G2, can't find the regular WR at the moment.
True, same size, same diameter of the tyre. The tyre constrution, tread design is entirely different. I am not sure what to do about the spare. The quote has been $178 per tyre.
Originally the tyres had 10/32 inch tread, current status is 8/32, so I should be able to get decent credit for the OE tyres.
I'd appreciate suggestions about the spare, I do carry a sealant, inflator with me and have never changed the tyre due to puncture, filled it up, drove to the dealership to get it fixed under warranty for free.
Michelin Energy™ MXV4® S8 - OE Tyres.

Nokian WR G2
