Did a search, and maybe it's out there, but don't see any comments on S tronic and fuel economy. Specifically, what is the impact on fuel economy for each gear setting?

D vs. S? or even D vs. S vs. M1-7?

Part of me doesn't want to know, but interesting to think about.

I'm sucking down tanks of gas pretty quick, but then again, I just got the car three weeks ago.

Has anyone looked at this or know the impact gear settings have on the S4's fuel economy? Definitely depends on how you drive regardless of setting, but if anyone has paid attention to this would be great to hear.