The M110 is indeed an awesome, but extremely thirsty, engine. If I was going to have a car that gets 12-14mpg it would be a 500SEC or 560SEC, not a W123 280....

And, 617 is best, simple as that. Though the M103 is pretty sweet too, I was having fun with mine today.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
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'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)