To revisit the engine question for a moment; is the engine in the M92 300SD more trouble prone than is typical for a Mercedes diesel? As fate would have it, one of these appeared in one of my local ad rags-mileage not stated. It has piqued my curiosity sufficiently to call for more details. How is a turbo diesel overall compared to the 3.2L 6 cyl gas engine in the S320, the only other engine configuration I'm looking at? My overall impression of diesel automobiles isn't very favorable. I hate the look of the tail of the car covered in soot. Are the turbo diesels any cleaner burning?