From what I've been told an HID bulb actually generates less heat than a Halogen bulb...don't ask me how it's just what I was told.
I am waiting to get an output shot of an HID bulb in this housing with the factory projector as well. I agree it looks like the housing should be able to handle the HID bulb but I am not going to blow $50 to find out just yet.
So far I don't mind using factory bulbs.
Also this headlight does not come with factory HID's. It is a Bi-Halogen projector.
Chrome... in moderation.