Here's my write up on converting Hella 4000 to HID without any drilling involved. This allows you to use the existing plug that the light came with.
Materials you will need
-A soldering gun and solder.
-shrink tubing or electrical tape.
-Wire cutter and strippers
I didn't really take much pictures. I drew a little diagram on how to do it. Hopefully it helps.
Assuming you are wired off a relay. This is what it should look like.
Your ballast to your lights has male and female connectors, on the Positive and Negative coming off the ballast and lights.
Cut the connectors off (cut them as close to the connectors as possible so you will have alot of wire to work with.)
Now take apart your hella 4000, remove the old light bulb and install your HID bulb (h1). inside the die cast housing you will see your old plug for the halogen bulb. it should be brown and white, cut the ends off and strip them.
Brown is Negative and White is Positive
after you installed your bulb into the housing, start soldering. you want to solder the Brown to Black and White To Red, after soldering either shrink wrap any exposed metal on the wire or electrical tape it. when you are done re assemble the lamp.
Now, granted that you already have the ballast connectors cut and stripped take the Hella harness and strip the blue and brown wire.
The Blue is Positive and Brown is Negative.
Solder the Red to Blue and Brown to Black. once done shrink wrap or electrical tape any exposed metal on the wires.
Now everything is ready to go, your ballast are in a secure spot, go out and enjoy your lights.