Gasoline is refined from crude oil and can contain impurities and minor inconsistencies. Because of this, it is standard practice for additives to be mixed into gas. This means that one person can fill up their car anywhere and get relatively the same product. Despite that, there are companies that claim their gas is the cleanest or best for engine performance.
Top Tier gasoline
Automakers around the world agreed that government requirements for fuel additives were not adequate since they have not changed to meet the demands of modern engines. Now, if a company can prove that their gas has additives and detergents that keep residue from building up on valves or in the combustion chamber, they are qualified to call themselves a Top Tier gasoline supplier. This type of fuel is formulated to keep engines running efficiently. There are multiple companies, such as Exxon, Shell, and Conoco, that all have different formulas for gasoline that all qualify as Top Tier. Automakers claim that these requirements make the gas better for modern cars.
Is Top Tier gas really better though? Technically it is, by virtue of being engineered to pair with the demands of modern engines, but the difference would be hard to notice. No manufacturer is going to make a car that only works with one brand of gasoline or a car that could be damaged by using gas that comes from any normal fuel pump. The standards for gasoline in the US are already sufficient to ensure that every single gas station sells a reliable product that does not harm valves or combustion chambers.
Keep in mind:
Always fill your car with the recommended octane fuel
The recommended octane for that specific vehicle should be written either on the gas cap or on the fuel filler door
The vehicle’s manual should specify what octane is optimal for that vehicle