baseline yung na sa manual (down to 89 RON yata puwede). Then variables sa suppliers and stations in terms of additives so di lang sa octane kundi sa detergents etc...for modern cars kasi, the ECU adjusts its parameters so sabi ng iba, better to stick to one para once optimized, wala nang re-tuning ng parameters. Then there's the condition of the cars.

Bottomline, what works diba? Kung saan hiyang yung makina vis-a-vis your driving style.