Both mods are great, especially if the mirror one is possible on a Y2000ish MB
I would like to try the headlamp mod first (I might use the foglamps instead of the sidelights at the front as it lights the ground up in front of the car - handy for puddles!). Personally I will try to avoid "tapping" any wires and will go for OEM connectors and junctions for a factory-style install and easy, damage-free removal if required.
It would be great if you could take some pics of the wiring, post a clearer circuit diagram and detail a shopping list of parts and tools required. I would move the thread into the HOWTO section if these conditions were met. We should also break up the thread so only one mod is discussed in each to avoid confusion!
Thanks for all your help so far!