The label Premium kind of makes people think it is better gasoline. It isn't. For those in the know, you can stop reading. I just want to make sure people understand that Premium is no better than Regular. In fact, it is basically the exact same gasoline but has additives to increase the octane level to delay ignition for engines with higher combustion pressures to prevent knocking (aka premature ignition) under heavy loads. Yes, you can go up or down 1 or 2 octane numbers with no problem. My truck recommends 91 octane. I run 89, unless I'm pulling a trailer, then I bump it up. If I run 87, which is common outside CA, I can tell the difference in performance when pulling a trailer or climbing a mountain on the Interstate.
Want to foul an engine? Aviation fuel (non-jet) is typically 105-115 octane. Put that in an assembly line car and see what happens.