Stock halogen headlight housing to HID?

[skybuster2]

I have a 2002 A4 with HID headlights.anyone know if you can convert a stock halogen headlight housing to an HID? I bought a new stock Halogen headlight housing on ebay,I thought it was an HID but it wasnt. it looks like the same housing except for the socket/Projector is different. by looking at the 2 side by side it looks like I can change the socket/projector. and also I would have to make a hole in the bottom of the housing for wire to go through to plug in the ballast,but there is a space there for the ballast to mount in,just no hole to run the wires through to the light bulb.
Skybuster

[dfresh000]

pretty easy.. just need a large hole cutting drill bit, the gasket that comes with the HID kit, and some silicone sealant to seal up the hole. Drill the hole in the back of the housing, use the gasket to guide the wires through & then seal up the edges & wire gap with the sealant. Did it on my car 2.5yrs ago & no issues or fogging whatsoever