Good analysis JPH.
You raise a point about the canisters not looking the same height in pictures. I measured mine from the ground and they're the same on my coupe. Unless the pictures are taken from exactly the middle an optical illusion may make one look lower than the others.
IMHO, the resonance at 2,000 rpm is there with all systems. Before my reports, AA guys were saying there's no resonance. Well, I heard it and measured it, both stock and AA Signature. I think that the owners of all systems downplay the noise. My reported 1 dB is very small, but real. BTW, my cars sets off alarms in both my office and apartment garages.
Ok, you've done the analysis, which will you buy. Will you flip a coin to decide?
I don't think that you'll go wrong with either.