Understanding RON (Research Octane Number) will give clear picture of which petrol to choose.
The Z33 Stock engine optimized for RON96 for both USDM and JDM. You can run using 95 or even lower, but there may be some engine knocking happen especially when you engine is hot. The Z engineer has done all the calculation to make the stock engine running smooth, so we better follow.
Actually relationship between of RON and engine is quite complicated, but most people misunderstand that RON = Power, but actually is not. It can be explained in simple manner like this.
Engine is powered by mixture of Air (oxigen) and Fuel (A/F), this mixture is easy to explode. It normally explode when sparkplug ignites, then push piston to the bottom. Knocking is something like "Pre-explode" of A/F in the "piston cylinder" when it is hot. meaning that the "knocking" push the piston down before it goes up completely. This process reduce the car performance and hurt some parts of your engine.
RON is actually Octane added to petrol to increase the "Pre-explode" resistance level of A/F mixture. So the higher RON you have, the A/F mixture will not explode by it self when your engine hot, meaning the combustion is more controllable.
Malaysia is hot country, so I think higher RON is better. In cold country or winter, lower RON can be used.
Another factor cause knocking is engine compression ratio, so if you modified your car later, you need higher RON number petrol to make your engine smooth. That is why, all racing fuel have RON level more than 100.
I hope my explanation is acceptable.
