FiTech Dual Quad

Changing the fuel's octane ratings does nothing for power if you don't tune for it.
Higher octane fuel is usually not 'better'. It just has a slower burnrate to prevent pinging. But the slower burnrate means you can now further optimize/advance your ignition timing, and that as such could make more power.

If installing the scoop raises the AFR number this means the scoop is leaning out the carbs. Most likely because of cooler airflow.
Denser air versus same amount of fuel = leaner.

Things get even more fun if you start digitally controlling the ignition timing as well.

Can you tune the individual injectors on this system?

Side note
I wouldn't run Champion plugs even if they paid me money for it.