You don't have to buy the fluid from a MB dealer. The fluid is made by Febi. It is available through Fastlane I believe, or any of the other on-line MB parts places.
1994 MB E320 Coupe (199,500 mi)
1992 MB 190E 2.6 (173,000 mi)
1983 Porsche 911SC (148,000 mi)
2004 Volvo V70 2.5T (198,000 mi)
President of CT/Westchester Section