Re: 20 K Service
20,000km is about 12,000 miles.
I'm not really on any schedule. I take mine in at the end of the summer and have the oil and filter changed. The dealer checks out the rest of the vehicle, but it has needed nothing. I put 10k, 10k, 6k, and so far 2k miles on it each summer. The beginning of this summer I installed K&N air filters and threw away the neat M-B stock filters (it never amazes me to see all the M-B parts on this baby). I usually do the oil before the wrench icons appear. I occasionally add a container of fuel injector cleaner and then run it at high speed for a distance - we can get autobahn 130kph here without much police problem.
I rotated the tires once. I'm thinking of changing the brake pads to Rotex or equivalent next summer to avoid all the dust.
She's a very low maintenance car.