More input, and I can provide a "before" and "after" perspective, unfortunately for me. What I mean by this is that 6 weeks back, I got into some speeding trouble. Forgoing the detail around that mistake and to stick with answering the Q on mileage....I had owned the car for about 2+ yrs. prior, and basically used it around town, suburbs, very little highway, but certainly also very little stop and go, but driven aggressively. Over this period with no thought about mileage I was getting around 22.7 mpg avg. So not bad at all.
After my stupidity, I decided that since I need to correct my behavior, I have not been using S regularly, just C, and instead of showing the AMG performance screen on temps, etc. I am watching the MPG avg. screen from reset some 6 weeks back. So, somewhat "egg under right pedal" you can say, no eco mode, I don't know how much you can trust someone that admits to struggling with the love for the right pedal, but I've been doing good. And given the same type of roads, more or less, I would actually say I am a bit more around town speed over this period, I am.......guess what......avg. 26.7mpg. If I actually had some real highway time I would likely be avg. around 27+, pure highway I can see avg. 29 possible for sure. I guess this also shows how much I loved that right pedal, I just have to save that for a local roadcourse if I choose to want to really work the car.
But my perspective is if you don't open up a 45 frequently you can get real decent mileage. I do anticipate that the 26.7 avg I am currently at will continue to trend down a bit as I get more weeks, but still think it will settle in around 26, over 3mpg more staying out of the gas given same driving roads.