Wow, this is really cool. While I know that engineering fields tend to parallel one another, I never would have expected my musical background to help me understand cars!
That said, I want to back up to one of these ongoing puzzles that seems to confuse everyone trying to wrap their words around it... the "power-efficiency" vs. "fuel-efficiency" morass. Maybe you can help get me unstuck here...
I'm starting to understand how tuning the intake response can help you generate more power in targeted RPM ranges. But here's where I'm stuck -- Am I understanding right that you're improving localized power-efficiency by allowing more air-fuel mix to be rammed in at each stroke? If that's the case, then it seems to me that this kind of efficiency is the opposite of what we're after -- we'd have the engine using resonance to become a more mechanically-efficient fuel-gulper. Like a champion hotdog eater, timing the dip, chew, and swallow to "efficiently" cram more in before the buzzer. But me, I'm a hypermiler -- I'm on a diet! How can hotdog-eating-practice possibly help me eat less?
I might buy it if the resonance principle will somehow also allow the engine to run off of a leaner mix. i.e. "The intake can now cram more air-fuel in, but doesn't because it doesn't need to, due to the cascading resonance effect." But so far that's a few layers of system dynamics beyond what I understand about car engines. Maybe if you can make an analogy to loudspeakers?