New mileage standards are on their way. 39 mpg for passenger cars by 2016. I understand that the 39 mpg would be an "average" among all models of cars that any particular automaker sells, but I'm not sure Nissan has many high-mileage cars to balance out the current MPG of the Z (26 mpg highway, 18 city... about 22 mpg overall)?
I would assume then, that the Z will need to be engineered to be more fuel efficient in the future. How do you think Nissan will end up doing this? Lighter weight? Lower horsepower? Less aggressive gearing? God forbid, a hybrid set-up? An electric Z?