Just FYI the light pattern is changed when using an HID bulb in a housing designed for halogens. IMO adjust by parking behind another car to ensure that you do not blind them at a stoplight. Then check the pattern on the road and the oncoming perspective to check for glare.
Technically the higher the rating from 4300k the lower the light output (assuming the ballast rating is the same).
I had to adjust mine down and there was still plently of light on the road.