Well I'm not sure about the older models. The 08 will shut down cylinders, up to 4, when posible. I just checked my MPG after my last fill up, and am getting Approx 24MPG. But I live in a small town and most of my driving is on state roads or interstate. And I'm sure when I'm putting my foot into it and the little display says my instant MPG is 1.7, that I am no where near 24MPG on that tank. I am the first owner of this car and know that it has never missed an oil change or a check-up.

But man if I got 10 MPG I wouldnt give up my GXP for nothing! I have never owned anything that had the performance and the handling all in one package. I have no plans to ever get rid of this car!