M103 engine Fuel Consumption survey?

[tino]

I have been driving 1986 300E with 3 litre engine, for approx two weeks and have put approx 1500 KL (937 miles) by driving mostly (approx 90%) highway at speeds between 120 km/h to 135 km/h (75 to 85 mph) I am very pleased with the fuel consumption which after each refill has been a constant 27 mpg (imperial gallon) or 10 ltr/100km. --- (my car has approx 170,000 km, new cap and rotor, NGK platinum plugs, 10w-30 synthetic oil, tire pressure all around at 34 psi.)My friend who has a much newer 300E but with a 3.2 litre engine drives like a old lady in order to conserve fuel. On the highway he’s a rolling roadblock because he set's his cruise at 100 km/hr (62 mph). He tells me he's average is only around 22 mpg (imperial Gallon) or 12.8 ltr/100km.
would be interesting to hear the fuel numbers from others please advise if your numbers are per US or Imperial gallon. Remember that the Imperial Gallon is 20% larger.( Ltrs/100km is realy the standard and would be the easiest for comparison).