All gas comes up through the same pipeline from many different companies. Say shell puts in 50,000 gallons and bp puts in 50,000 gallons. They end up getting mixed together in the pipe. Only the grades of gas are seperated by huge plugs that get rammed in after the gas has been added i.e. regular, mid, and premium. When the gas reaches its destination then it goes to a specific company say shell will pull out 50,000 gallons of gas that they initially put in. Then that "mixed up" gas from 10 different oil companies that is now the property of shell puts in their own additives, then the gas goes to the stations. Thats how gas is shipped and the only difference is a companies specific additives. Now on to octane/grade. The higher the number the slower it will burn. The only time higher octane will make a differance is if you are running a really really old motor with a lot of miles, or a high compression/forced induction motor at a minimum of a 8.5:1 ratio. If you dont believe me look it up, this is all true. Run 87 or maybe 89 in your china girls. Anything over that is a waste of money. BTW all the china girl 2 stroke motors exept the superrat-66 run a 6:1 compression ratio. The superrat-66 is a 7:1.