That's a specialty engine in new cars. In cars made today, you'd find that on a sports car. Older cars do often require higher octane gas because engine design

That's a specialty engine in new cars. In cars made today, you'd find that on a sports car. Older cars do often require higher octane gas because engine design was just worse back then. Less than 20% of new cars need high-octane fuel, and those that do are luxury/sports cars.