High octane gas shouldn't be necessary with the compression ratio your engine has. It might be coincidence, but if it helps, the only downside to running high test gas occasionally will be a few more bucks out of pocket when you gas up.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!