First thing I did for my XF (Back in Oct 09, three months after purchase) was replace the OEM high and low beams with Silverstar Ultras. Having a set of regular silverstars in my Ford truck for over 4 years, I thought it would be a long lasting mod. They have been in the car for 25 months now and are still going strong. Very bright and I got both sets from an amazon vendor for less than 30 bucks delivered. I also changed out the fog light bulbs with a 9000 series high beam bulb, that really lights up the road being brighter than the OEM fog light bulbs. The fogs are slightly yellower but the frontal visability is awsome with the ultras and the higher output fogs. I'm glad I did this upgrade, I just hear too many horror stories with HID's. Glad they work out for many of the members just not my cuppa tea.