I've got a 210 LCR and its stock except for an induction kit that was on it. To get to work, I drive from Hemel to Near Stevenage, but the back roads, so fairly hilly, and to be honest, driving to and from work, you cant really build up that much speed anyway, as its mostly single lane and busy.
Driving like that I can get 33mpg, but when I go see my folks I tend to use the A1M and M1, so, thats not so good
lets say 25mpg but thats caning it off the slip roads and 100mph+
Overall, a tank of petrol with a combination of both types of driving, I get pretty much bang on 30mpg, which I think is pretty good for a car that can be comfortable when slow, but awesome when not.