FWIW I installed HID on my 93 GS/PD back in Feb 06 and have had no problems with it. It does have the hi/low bulb using the servo to reposition the bulb's focus rather than two HID elements(?). One big positive is the brightness makes the bike very visible during daylight in bright west Texas sun. The only negative is the slow brightening of the bulb when first turned on. It has passed the Texas State Safety Inspection four times. I really apprecitate it at night and on low beam don't get flashed by oncoming traffic.
The slow brightening of the bulb, I understand, is solved by the new digital ballasts and I've been thinking about upgrading. Anyone have experience with the digital ballasts?
This is the place I got mine...