Kind of on the same topic...
I also have a 94 e320, and last night I tried to open the sunroof and it went super slow. I stopped about halfway in fear that i'd have to manually shut it. It did close normally except at the very end when the rear has to pop up to create a seal, it went super slow again. i just washed and waxed the car last weekend, and didn't have a problem before that. coincidence??