Gas with higher octane than an engine needs (for its manufacturer-determined compression ratio, timing, boost in turbo and supercharged engines, etc.) does not improve performance. In fact, because the higher octane fuel is less explosive, it will actually perform slightly worse.
To maximize performance and to minimize cost, one should use the lowest grade of gas possible, without knocking or engaging the anti-knock functions of the engines. Since modern engines won't knock enough to hear (precisely because of the anti knock circuit kicking-in before audible knocking occurs), one can only follow the manufacturer's recommendation and assume that grade of gas is working properly.
Putting 100+ octane aviation fuel in one's IS won't improve performance and will only drain the wallet faster.
If using higher octane caused an engine to perform more poorly then racing fuel would not be of a very high octane.