Go ahead and buy the Haynes manual for the W202. Yes, the engine covers the 4 cylinders but the manual covers so much more than just the engine that it is a worthy purchase C280 owners too. Body, suspensions, interior, airco, etc. You can buy a Haynes manual for another MB model that shares the same 6 cylinder engine if you want engine specifics. Or you can buy MB WIS software or something like All Data. MB also sells a disk for something like $120.
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!