Just curious, is it the bulb or the casing that make the projector headlights look the way they do?

Well, it depends on what you mean by the way they do..

The HID'* discharge the light (Ballast and Bulb)...while the addition of the projectors direct the light better then stock housings...

I think he means the "bulb" sort of look on the end of the headlight. You mean the shiny orb thing on the headlight, right? That'd be the casing. The bulb looks quite a bit like a regular headlight.

This is a typical projector housing.

well, what im trying to get to....if i were to put my hid bulbs in a projector housing, would it direct the light like a typical projector bulb?

There'* no such thing as a projector bulb. The same bulbs we use in our reflector housings can also be used in a projector housing/lens. If you're asking if you can install an "HID kit" in your stock projector housings, yes, you can, but at an absolute minimum, you will need to re-adjust your headlights.

what do you mean stock projector housing?