While some high-performance cars might *recommend* higher octane fuel (98 or even higher) for optimal performance, a vast majority of cars on the road today are designed to run perfectly well on 95 octane. If your manual says 95 or higher, then 95 is acceptable. If it specifies 91 or 98, you should use that grade instead. Using a lower octane than recommended can lead to engine knocking (pinging) and potential damage.