Originally Posted By: sciphi
Knowing my Buick has a terrible beam pattern, I elected not to get HID's for it. Now my fiancee's Honda has a great beam pattern, with a well-defined cutoff. It would be a good candidate for a HID kit when her factory bulbs blow.
If the Honda has reflector housings, it WON'T be a good candidate. It has a good cut-off with HALOGEN lamps. That's because the halogen filament is extremely small, and brightest in the center. Essentially, it's a point source around which the entire reflector is designed.
An arc-filament lamp (HID) is very different. The "filament" is much longer, physically, and the brightest areas are at the ends, not at the center. You essentially have two extremely bright hot spots that aren't in the "center" of the reflector. This is why HIDs produce so much glare in reflector housings: the light source isn't where it's supposed to be.
If the Honda uses HB4 (9006) bulbs, the best thing you can do is upgrade to HIR2 bulbs. They put out almost double the lumens. Technically, this "mod" is illegal, just like an HID retrofit, because the bulb used is not the intended bulb. But the difference here is the optics of the lamp aren't changed, because the source of light is from the exact same place as the original bulb. The HIR2 and HB4 bulbs both have the filament in the exact same location, in 3D space. So it's a much safer option, and still gives you a very noticeable increase in forward lighting.