After the occasional drive at night, I really wanted to improve the lighting situation. I'm not sure about now, but at the time I was looking to buy OEM HIDs they had to be shipped from Europe, were fairly expensive, and non-blem, brand new HIDs even more so.
Anywhoo, I managed to find someone selling new OEM HIDs (manufactured by Bosch) and once they were installed I needed to aim them properly. I followed some easy-to-follow instructions on visually aiming headlamps from Daniel Stern Lighting.
Here's a quote from the instructions that I find funny in a bang-my-head-against-the-wall kind of way:
US DOT VOL and VOR headlamps cannot be visually aimed horizontally, and in many cases, cannot be aimed horizontally by any means at all, because no provision for horizontal aim adjustment is provided. [This is because US regulators believe there is no way to define a visual cue, such as a kink in the cutoff, that would allow accurate left-to-right placement of a headlamp beam and that cars will not get in fender-benders that will knock the headlamps out of horizontal alignment. For what it's worth, the Europeans have been successfully aiming their headlamps vertically AND horizontally since 1955. -ed.]
Anywhoo, since the HIDs were European-spec I was able to aim them both vertically and horizontally. I did this soon after I first purchased and installed them, and again just tonight (Ah HAH! The genesis of this post is revealed).
Some final notes: to protect my investment I also purchased Lexan headlamp covers; I disabled the daytime driving lights (DRLs) prior to installing the HIDs; I installed a rheostat (not required) to control the leveling motors found on the HIDs.
Update 11MAR2007: Hmmm... in case I wasn't clear, fyi I installed the HIDs almost two years ago and decided to do the write up now, since I didn't have a blog back then--I just had an old fashioned website.