It depends on the car. A lot of the newer cars have ECU’s that adjust the timing to take advantage of a higher octane. I know a lot of Toyotas reccomend premium in order to achieve the best performance, and that’s what the top power output on the stock car was achieved using, but they will still run fine on 87 octane.
I’m sure the gains aren’t all that much when you’re talking about a stock NA car, but still, there is a difference.