I have 07 3.0si coupe,I get 28mpg with mixed driving.i once got 36.4 on a long journey-but was "driving like miss daisy" and almost dropped into a coma doing this so don't try this at home kids.i have now decided that as the z is my every day driver every time I fill her up I'm just going to remember the 6months in a 360bhp evo 7 which would do 12mpg on a run or 4-6mpg on a track! 
