Theres a C6 in the family, and I've driven it several times....
Even with the 6 liter V8, I can get the MPG on the heads up display to read well over 40 MPG regularly, cruising along. Up until about 60 mph, if you drive it like a normal car, it gets well above 30 mpg almost constantly. Even at 75 mph the engine is still pretty much idling. I'm sure he could do better, but I bet he isn't driving it like I am, and I don't blame him.
