I don't think I've gotten more than 180 on a tank, but I've only had the car for a month so 80% of my driving is spirited. And I always have the Power button on, even around town, because it feels better to me.
I have an old Land Rover that gets the same mileage (~12mpg), so I'm used to it, but the difference is a grumble every time I have to fill up the Rover, and I smile every time I fill up the M3 because it means I get to go another round. Worth every penny!
2009 E90 M3 . Jet Black . DCT