It seems like latley everyone is worried about fuel prices and emissions rather than power, but I believe there is a way both can be had; by swapping a diesel engine into an earlier, lighter vehicle.

While there is no doubt that new emissions laws are killing our fuel economy, old musclecar guys have it much worse.  A Camaro with a 600hp big block Chevy will get about 10mpg on the highway on a good day.  The trip into town that cost $5 in gas a few years ago now costs $20, and many of these old cars are being driven less due to $4.00 a gallon gasoline.  While it's true that new diesels might only get 15mpg, they have to move an immense amount of weight, as today's diesel trucks have gotten pretty porky.  My advice?  Stick a newer d-max engine into an older Camaro, or a Cummins into a Duster, get 30mpg, and still make 600 horsepower.