Originally Posted by Steve - UK
HID kits are on the market but be wary of cheap poor quality ones. They can be fitted as a DIY job but are a bit of a fiddle. I very nearly went along this route, as the XF standard headlight bulbs are well known to be dull! Instead of HID I went for simply upgraded headlight bulbs and the difference was amazing. Halfords do a range of suitable bulbs (Type H7). I went for Zenon 6000K bulbs to replace all 4 (high beam/low beam). These have a slight blue effect. The higher the number (ie 8000K), the bluer they are but my choice was twice the brightness of the standard ones. They are a devil to fit, so get the Halfords man to fit them for you! Good luck!
I got the brighter bulbs like yours as soon as I got the car but even so, I understand you can't use the very brightest ones because they can damage the plastic headlights...not 100% sure on that though. Even so, it's still nowhere near what I'm used to on roads that have no street lighting. All things considered, I think I'll have a look round for a good quality kit & have it fitted. It can't be any worse can it?