To squeeze 350 HP from 4.4 liters (80 HP per liter) Suzuki started with a new cowl design that features dual intake louvers and passages lined with rows of small vanes or fins designed to convert water vapor to heavier particles that are then drained away. The result, according to Suzuki, is a flow of dry air to the engine that is never more than 10 degrees warmer than ambient. Cooler air makes more power, of course. Intake and exhaust ports are re-shaped, and the engine features dual 10-hole fuel injectors for each cylinder that deliver a fine mist of highly atomized fuel and eliminate fuel puddling before the intake valves. The range of the variable intake camshaft timing is increased to 30 degrees from 20 degrees, and the engine is fitted with shot-peened slipper pistons that are very strong and very light weight. WOT operating range is 5700-6300 RPM. The compression ratio is a very high 12:1 and to extract maximum power the motor should get 91 octane fuel.
The article this comes from recommends 91 octane for best power. This usually means some sensor does something like change valve timing to reduce the effective compression ratio as needed to prevent detonation. Multiple fuel injection events can also mitigate detonation as will the cooler incoming air. Seeing as we are not on Florida the incoming air will be on the cool side of what this is designed for, so maybe 87 octane up here will perform as well as 91 octane in Florida?? Just a WAG on my part.