If the engine is not designed to run high octane you gain nothing by running high octane.
Contrary to popular belief, there is no added performance from running higher octane fuel.
The only time you are going to sieze an engine from preignition is by running it really hard on a very cold day.
One of the really cool features about the Polaris I currently own is the octane switch. It has 2 positions: regular and premium. If you are able to find 93 octane fuel that you know is of good quality, turn the switch to *PREM*. This will advance the timing and give you maximum power. If you are unable to find 93 octane fuel or are unsure of the quality of fuel, set the switch to *REG*. This will retard the timing and will safeguard aganst a siezure caused by preignition. Of course, if you have an SRX or a SX Viper the sled does it on its own. If I remember my Yamaha literature correctly, when it recognizes preigntion it will retard the timing by 1 degree untill preigniton stops. At some point if the preignition doesnt stop it will go into a "limp home" mode where it limits the rpm to 5,000. It helps prevent a siezure but still allows you to make it back home.
Hebi