HID bulbs create an 'arc' between two electrodes.
That arc is not in the same location as the filament of a normal halogen bulb.
Therefore, your OEM halogen reflector would not 'project' the light properly with an HID bulb installed and all you would do is blind oncoming traffic.
The only proper way to have HID bulbs in non-HID headlights is to take them apart and install a proper HID projector housing inside the halogen housing.
Other threads have reported success with that method.
Still other threads talk about the new LED H11 bulbs available on the market.
Personally, for now I went with the Osram Nighbreaker bulbs from PowerBulbs:
OSRAM Night Breaker Unlimited H11 (Twin) | PowerBulbs
We shall see how long they last...
They do not have the "blue" appearance of other tinted bulbs.