I live in florida and have always gotten great gas mileage. Trip odo B is still the same mileage as the cars odometer and in 5000 miles my average speed is 29mph and my avg mpg is 31.7 indicated. Almost all my driving is ten miles or less. But my 5mt warms up fairly quick (seems like its quicker to watm up with the mileage on it now).
I don't think the engine is really whats needing the long break-in. I think its all the drivetrain "loosens up" a bit by 5k or so. Anyone wanting to try something to see if they notice a difference- try running Amsoil in the engine, transaxle, and rear. My car seemed to get a slight boost in mpg's when changed out all the factory filled stuff. Just my 2¢