This might sound really obviuse but it really depends on what fuel you use (Im sure some, if not most of these guys here use BP Ultimate or Shell V-Max or whatever its called). And what kind of driving you do (town or motorway). I know my car isnt the same engine as you guys, but I was getting poor MPG when I first got mine, it wasnt till I got on the motor way that I realised it was because I was doing all town driving (26-28) but as soon as I went on motor way it went right up (30-34 depening on speed, obvisuly), and now that I regularly use BP Ultimate its even higher.