Welcome Dank! The 2 things you mentioned K&N and Xenon ) are great minor mods for the XF depending on your taste. This will add mpg ( K&N ) and the xenon lights for added effects at night as you want your fans to keep their heads turning day and night

If you browse some more, there's still a few mods that we made and has been happy with it. Enjoy your XF and keep smiling