Hi M@v3ri1ck,
Not sure if this would apply to a 2017 XF, but in my case (2011 XF-S) there was a musty smell from the pollen filter (replaced before collection) and a rattle from the window guides in the driver's door (also replaced or fixed).
Also, a few months after I got the car, I had to replace all 4 brake discs and pads, not covered by warranty - c£950!
Final thing, the previous owner had fitted £60 Chinese 'Triangle' tyres - horrible in the wet. Also replaced by nice new Pirellis for £800.
MOT next month - eek!
Love the XF though!
Cheers,
Jon