350 HP ICE vs. 350 HP Diesel?

You are hard to please. haha I could have said the Eco boost engines are more fuel efficient because they have turbos (some have 2) that squeeze more horsepower out of a smaller displacement engine thus using less fuel while providing good performance. But the key point is that it is the turbo that allows the Eco boost engines to be more fuel efficient while still providing enough HP for good performance. A small engine without a turbo is even more fuel efficient but a dog to drive unless the size/weight of the vehicle is reduced. Lots of variables to consider. Wanna throw in wind resistance/air flow? We can beat this to death!