I have to differ with that. the 616 will take more fuel, and make more power. Enough to be noticeable. Stock I was able to make 40 mph in third on a mountain grade, on the same grade with ip adjustments only I made 50 in third. With other mods now I make mid 50's in fourth. No turbo.

Clearly Mercedes has tuned it very conservatively most likely for emissions. There is a lot left on the table.

__________________
1977 240D turbo