I don't think there is anything wrong with getting an E320 but don't do it because you think it's cheaper to operate. Gas mileage is at best 1 mpg better and maintenance seems to be about the same. When you factor in the additional cost of the periodic head gaskets on the 104 motor the 119 might actually be cheaper to maintain. And I don't see much difference in market values - if the 420s are higher in price it's negligible. With the additional cylinders and lower rear axle ratio it seems to me very likely the 119 motor is going to have a longer life.