I'm a Mercedes Diesel guy, 5cyl diesels are right in the middle. I have the "OM603" Inline-6 diesel which only came in the E-Class for one year. It was the most powerful diesel they put in the W124. The later cars had a 5cyl, it is slightly slower but does better on fuel. Several of my friends have the "OM602" 5cyl cars, my car runs away on the highway (19+HP 22+TQ) but they'll go a little further, about 1-3mpg better.