I get a vibration too but only when I first start out after the car has been sitting for a while. I tend to only drive the XF on the weekends which means the car sits for several days. The tires actually get flat spots on them. It takes several minutes of driving or about 10 miles before they get round again. I reduced the problem by parking on some used pieces of carpet. If you can find some old used carpet to put down on the garage floor it will help. Parking on two pieces of carpet is even better.