My only input is that the G56 6-speed is junk, it cannot handle the torque of the 6.7 if you do any heavy towing at all. I sure loved the power and smoothness of the 6.7 and really didn't notice much of a difference in MPG. I really hate the 06-up interiors compared to the 04-05 and the looks of the bugeye headlights don't help the 06-up too.