Bulb failure doesn't cover headlamps.......
you will invalidate your insurance by fitting them and fail any future MOT due to the headlights not been designed for HID or approved. No headlamp washers or automatic self levelling devices fitted... (not sure if its in force yet)
The GP headlamp in its design scatters the light all over leading you to blind oncoming drivers....
some do not fit the bulb holders properly due to their size as well
Do a search this has been covered in this section before before before