There certainly is a difference between MB antifreeze and anything green. Mercedes antifreeze is Glysantin. See the following articles:
http://www.imcool.com/articles/anitfreeze-coolant/G05-Glysantin.htm
http://www.valvoline.com/products/cooling/technicalbulletin/tb_zerex_antifreeze.html

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles