Here's all I'm going to say:
I just filled up, and got approx. 20mpg on a STOCK GTP driving around the CITY. All I did was not rev it to 3000rpms like I normally do. (I wish I could tell you exactly what I got, but I left the receipt in my shirt pocket...which is now in the wash.
) I haven't even done any of the mpg-improving mods yet.
So, I don't feel that paying a bunch more a month for a new car just to slightly save on gas is worth it, not for me. Besides, I wouldn't give up the power...until they can make a hybrid or electric car as powerful & still as cheap as a sports car, I'll stick with gasoline.
If commuting was an issue (with it's not for me, thank God) then I would look into moving or a new job before a new car.