Mine is a 500SEC so it's a European spec m117 5 liter engine.
I don't know if the slightly higher compression ratio and different cam timing would make all that much of a difference versus US spec motors though.

The 300SD still has stock bits on it, as I haven't seen any need to fiddle with it's exhaust plumbing, nor any real performance gain to likely be had.

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-Josh
Testing the cheap Mercedes axiom, one bolt at a time...