My 190D auto with 2.2 na has averaged right at 36 mpg over 5,000 miles. Running over 65 mph loses about 10% in fuel mileage. Best tank was 38.6 and worst was just under 34. I could see a 5-speed with more favorable overdrive gearing (auto is 3500 rpm's at 70 mph) could easily push you into the low 40's.

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