Honestly this isn't even worth talking about🙄
Air temp, manifold pressure, engine temp, and exhaust O2 are all used by the ECM to to alter injector pulse width, ignition timing, and manifold vacuum. So unless you feed it something far to one end or another of the combustible spectrum (water or diesel fuel) then the torque output SHOULD be relatively stable.
Therefore, without precise monitoring equipment you aren't going to notice a difference between 87 or 91 octane fuel anywhere but in the thickness of your wallet.
As far as "HIGH PERFORMANCE" altered motors are concerned.... Outboards are already"high performance" by design, so tweeking/flashing for even MORE performance comes at a cost. And that cost is
R-E-L-I-A-B-I-L-I-T-Y. Engines tuned to go extra-fast don't do it for very long. You'll only get there quicker if the distance is short.