so this amazon page leads me to believe the sachs and stabilus are the same:
http://www.amazon.com/Sachs-12446304...8598234&sr=8-1
and the search for the autozone part number gives results that fit tons of mercedes models:
http://www.amazon.com/s/qid=1238598408/ref=sr_st?keywords=SG203004&rs=15684181&page=1&bbn =15684181&rh=n%3A15684181%2Cn%3A!15690151%2Ck%3ASG 203004&sort=-price