Here in Pittsburgh I can use 87, 91, or 93 octane. Other than an occasional fill up with 93, I normally fill it up with 87(and it runs just fine). Now that I have the Battery Tender ready to connect, the fuel stabilizer ready to add, and am preparing to fill the tank for winter storage, I am not sure if I should fill it up with the 87or with the 93 octane. Any thoughts? Thanks.