I didn't say I used Premium in my SC. Only my in my small engines machines.Feel free to waste money on higher test if it makes you feel better. Unless you encounter knocking under high loads/high temps there is no reason to run anything but 87. Hyundai built the engine to run on that octane, so it will not run better or get better mileage on higher test. My ancient Ranger needed 89 when towing in FL during the summer with the A/C on, however modern engines have much better spark control to the point that knocking / pinging is a thing of the past.