How much do you like your motor. Do you like detonation? Its says premium for a reason. Your engine is designed for it. its not recommended...its required. Poor drivability Less power worse gas mileage detonation (which leads to sever engine damage) failed emissions(ive seen it muliple times and if vehicles fail emissions what does that tell you?) need i say more? You act like the hundreds of engineers flipped a coin on what fuel sticker they would put on the fuel door.