Mike, Octane booster [generally a mix of aniline, toluene & ethylbenzene] costs too much to be effective in the quantities you'd need to boost octane in pump gasoline. I'd suggest you visit your local small airport & buy some 100LL AV gas & try mixing that stuff with pump premium. AV gas adds some tetraethyl lead to the gasoline mix - something long removed from "street" gasoline. I think you'll find the engine [up to ~ 12.5:1 static compression] will like the stuff & so will your wallet!
