I have the HD HID dual bulb setup and converted the high beam to an H8 HID unit from (DDM?). Very good improvement in long distance range. I did find it very sensitive to vertical adjustment. But the HID high was a nice improvement over the conventional bulb.
Doesn't an HID Hi-beam bulb take a while to heat up before it comes up to full light output. BTW the instructions that can be downloaded from the HD Site list the replacement Hi-beam bulb as being Halogen.
I use the Sylvania Super Bright bulb and it makes a big difference. I also have PIAA ditch lights. They are bright but expensive, I think they were over $400. The ones I have are a flat wide beam, you can see in the ditch almost as good as you can see the road. This is nice for avoiding critters.