Thanks Turbo, I've got an 04 so mine probably doesn't look any different.
I've never been terribly impressed with some of the rubber components on my car. Nothing major mind you, wiper blades, gas cap umbilical cord to be specific. But they disintegrated long before they should have. I guess I shouldn't expect the flex disc to be any different.
It would be interesting if some 07 an 08 XF owners would be so kind to check out their discs to see if their's look OK the next time they get under their cars, and let us know how they look.