I'm averaging about 26.5 mpg going 32 miles 1 way to work, 5 days per week at 70% highway (74mph cruise control). Minimum city driving and zero highway driving on weekend.
Best ever, per tank: 28.9mpg......worst ever: 24.3mpg
I did the same thing you're doing now......asking actual owners what they got. My surveys of about 14 different drivers around the US came in at 27mpg highway (60-80% highway vs 40-20%city).
Try ecomodder.com too. I found a guy there who tracked his mileage, driving habits, gallon usage, etc, etc. I found it to be right in line with my actual numbers.
I also test drove an MS3 GT, and compared the MPG numbers the car displayed (resetting the data to zero before leaving dealership) vs the sticker. This gave me 26.9 highway.
My driving habits are: Easy on the car at start-up, drive the highway portion w/ cruise and then on the last 2 miles of city driving, chirp 1st, 2nd & 3rd (trac cntrl on) at each light.
Have fun and let us know when you chirp 4th!