First off...go here and view...very easy...

http://brandon.importtransmissionexchange.com/benz_files/lights.htm

Secondly...
55/100w bulbs (off of a 12.5v battery) pull 6 amps on low and 8 on high. I measured it with a Amp meter before I installed them in the car.

I would not recommend using stock wiring as anyone with a w126 knows, when you hit the heater switch your headlights dim and all sorts of power dropping issues.
Its not a matter of excessive amperage per-say but more a matter of voltage drop by the time you get to the end of the wire at the bulb. Light output drops significantly as V drops away at a small rate.

The upgrade to 55/100 is amazing and in the time I have been running them, only had one person high-beam flash me (there was a hill).
My friends say its acceptable light output in their eyes when I am behind them. The cutoff on the Euro H4's helps this a lot...just make sure you take GREAT care and aim them CORRECTLY..

Brandon