I've not done this procedure, but have done some similar work in the past. His instructions are fantastic for this type of procedure. Think each step through before you do it, and don't be afraid to ask questions about each one here. Lot's of folks here would love to help out.
Only suggestion I have is get some of the fender snaps for replacement. I usually end up eating a few each time I remove them.
i looked at the xenon depot link, and while the end result does look brighter, the cutoff seems the same (look at the two shelves in the before and after pics in the garage). I think the headlight adjustment under warranty would be the best idea, since I have no issue with the brightness, just the cutoff.....thanks for the info.
HID's give a more pure white light output, and when properly adjusted, should have the same cutoff as the factory lights, as to not blind oncoming drivers at night.
That's the most common misconception about HID's; it IS necessary to re-adjust and re-align the cutoff height for the HID bulbs since some HID bulbs have a longer focul length, and thus require physical adjustment "down" to keep from blinding oncoming cars.
From what I read, however, this vendor's HID bulbs were specifically designed with the same focul length as the stock bulbs, so no major height adjustments should be necessary. But it's still important to check.
Factory headlights have a yellow tinge to them since they're incandescent (compare a standard household 60w bulb to a fluorescent "twisty" 60w equivalent bulb, you'll see the difference in a purer light output) which means that they do not light up the road "as far away" since the light is not as pure white as HID's.