I am some what sure that all M104s have CR of 10 bar the M104 AMG36 at 10.5
I have official merc brochures at home covering the 300-24 onwards. Ill check and confirm.
I am also sure that M103 came in 2 CRs, regular 9,2 (9.1) and the one that came on early 4matics and W126s with Cr 10.0 ( the CR was stamped on the Block of the M103.)

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Jay,
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-1995 Blue W202 C36 AMG (M) SOLD ;(
-1995 Black W140 S500 (Lady)
-1992 Black W124 E300 (Dima) (Ex-Mosselman
Twin turbo Kit).
-1988 Black W124 300 E 4-Matic.(Nadeen)
-1983 Brown W126 500SEL.(Old Lady)(Sold)
-1981 Gold W123 280CE.(Dareen)(Sold)
http://www.youtube.com/user/jayrasheed