[mahout]

[quote=zukered;358736]The manual indicates the following specs for non-Sport tires:

P175/65R14 81S

... which I read to mean:
175 mm wide
.65 sidewall aspect ratio
Radial construction
14" rim
load index of 81, "S" meaning it's rated to 180 km/h (112 mph)

How closely do winter tires (or for that matter, replacement tires) have to conform to these specs?

Do I need to budget for wheels to go with them, or would they just re-use the ones I have on now?

It depends. If you plan to change these fairly often, like twice a year, the cost in a couple of years will exceed the cost of spare wheels, which you can get from a junkyard or buy new from DiscountTireDirect already mounted with winter tires and balanced. You can change wheels with tires mounted yourself. And if you have a punctured tire you have a spare handy.
175/65x14 tires (and BTW there is a 175/65x15 too) measured under the metric regulations must conform at least within 2% of the stated measurements when pressurized at design pressure by manufacturer.
A 175 mm section tire lays between 172 and 178 mm wide. THe tread width is not specified but for most tires it will lay about 85 to 95% of the section width, For winter use, a slightly narrower and slightly taller tire is advantageous for better traction and ground clearance.

Likewise a metrisized tire must conform to: section width in mm (2xsection aspect in hundredths)/25.4 and added to wheel diameter in inches = tire diameter.
For 175/65x14 the diameter is (175x1.3)/25.4 and that added to 14" = 22.95".
We used 175/65x15 continental 'ice bears' last winter in the mountains very well and never got halted.

but we don't have anything like Candian winters so local success counts more..
PS if you need tires rated better tha 'S' there is heavy rethinking to be done here.