Hello all, first post here. As the somewhat new owner (almost four months now) of a '99 XJR in Boston, I'm already looking forward to the days of snow and snow tires. The price of an extra set of 18" wheels and tires is quite high, so I'm wondering what is the smallest size of wheel that would fit over my brakes? Ideally I'd get a set of 16" or 17" wheels and put snow tires on those. This question is especially relevant to me because the local Jag specialist sold me a 16" wheel from a Vanden Plas that I could use to put a spare tire on, as the car didn't have a spare when I bought it, but I've never used it, and don't want a nasty surprise if I do need to put it on and find out that it doesn't fit. Anyone have any experience with downside wheels on their XJRs? Thanks.

16" will fit on the rears but won't clear the brakes on the front. You need 17" for the fronts.