I have changed the whole front end of my is250 to HID bulbs the high an dipped beams were ok if you don't have giant hands took about 45 mins but the fog lights where a nightmare started at 6:30 finished about 11:30 their is a trick to doing the front left but only for small hands their is a little cap underneath the bumper you can move an get your hand in don't know if anyone has seen this but it is how I done my left hand side it means guessing with your hands but saves taking arch out but the right hands side was a nightmare.