Since I rarely carry much in the trunk anyway, I wouldn't mind at all taking up some of the space with a donut spare. If someone KNOWS for sure of a donut that will fit a '04 XF, I'm sure it would be helpful to everyone here. If the one now on eBay is the right one for the XF, then I may have to pick one up. Somebody asked the seller if it would fit; the bolt pattern is right; unsure of the diameter.