http://en.wikipedia.org/wiki/Holden_VT_Commodore
Thats what i currently drive.
No matter what im sure im gonna get better mileage :P a 3.8L V6 as opposed to this. According to the pre release mpg numbers im going to get the same distance in the 86 as i do currently with my VT, only the VT fuel tank is 75L and the 86's is only 50L

Not sure what that is in gallons sorry yanks