I have a set of brand new 19" BMW Stlye 298m wheels with Goodyear 255/50/19 Ultragrip Runflat tires installed. These are the factory approved winter wheels and tires for the X5M and X6M. They were bought brand new from the dealer for over $4,500, but my parents sold the X5 before they used them. Don't get stuck when the snow flies this winter on your summer tires. Be preparred ahead of time with this phenominal deal. My loss is your gain.
They should fit other X5 and X6's as well but you would have to confirm with your local dealer.

Asking $3,000

Pictures available on request.