When I purchased my 2010 WRX it had an estimated 25 MPG highway/18 MPG city. I haven't really paid much attention to mileage (since I drive the car somewhat agressively about half the time), but with gas prices on the rise I made a committment to try being a little easier on the car. I took a trip with my son (mostly highway driving) and averaged just over 30 MPG. For a while on the highway I was getting 33, after a few stops & a small amount of city driving it averaged just over 30. I live in Iowa so it's not like I was driving through mountains and when I say City, it's more like 'town' with very light traffic. Over the life of the car (10,000 miles total) I've averaged about 22.5 MPG, before winter it was more like 23.5 but starting the car up & plowing through some snow drifts brought down the average.
I was wondering if anyone had a similar experience, did they just low ball the mileage? The only upgrade I have is an SPT CBE which shouldn't make much of a difference.