As mentioned above, fuel economy numbers don't come entirely from the engine. Note that the 2015 Civic HF gained a 2mpg higher rating simply through lightweight aerodynamic wheels, thinner tires, rear spoiler, underbody panels and slightly lighter weight.I think, once we see the EPA testing results, that the Earth Dreams design is much more efficient than the r18a it replaces. The other things mentioned also contribute a great deal in the resulting MPG. Honda is no slouch when it comes to engineering. I have been impressed that the r18a is more efficient than Chevy's 1.4L turbo motor. Better mileage and lower emmisions, so this new 2.0L NA motor is bound to be better.
Power costs without a doubt. But you can reduce the impact of increased power through increases in efficiency.I think that it is fairly obvious at this point that power is not something that can only be had at the expense of efficiency. I think that is exactly what technological advancement has been focused on in recent years.