SWSportsman is correct. A friend who works at one of the refineries in New Orleans and also works the pipelines going from New Orleans to Atlanta, from Atlanta North through Knoxville and East through North Carolina informed me that all the gas is all the same now. Exxon, Shell, BP, etc., all use the same pipeline and that same gas is all dumped into the tanker trucks at the distro points. The additives are a ploy to make money. Even the ethanol content varies, could be less than 10 percent or over 10 percent. The gov mandates that gas has to have a certain amount of cleaning additives and they are all the same. Top Tier? Money can buy anything.