Should the Audi A5 use 98 or 95 gasoline?

[McAnna]

Audi A5 can use 95 gasoline, but 98 gasoline is better. Difference in octane rating: 98 gasoline is a mixture of 98% isooctane and 2% n-heptane; 95 gasoline consists of 95% isooctane and 3% n-heptane. Difference in anti-knock combustion capability: 98 gasoline has higher anti-knock performance and power output; 95 gasoline has average anti-knock combustion capability. Gasoline appears as a transparent liquid, refined from various petroleum-derived components like straight-run gasoline, catalytic cracking gasoline, and catalytic reforming gasoline, blended with high-octane components. It is primarily used as fuel for spark-ignition internal combustion engines in automobiles.