Every major chain in America is "toptier". All "toptier" means is that they put detergents in the gas to help remove the sludge/residue that ethanol (corn) creates in your engine. It sounds a lot better than "Ethanol residue remover". It doesn't have anything to do with the quality of the gas, it's just a marketing jargon for adding detergents. The gas at any busy Arco should be okay. You are, however, more likely to get gas with deposits in it, and the quality of the gas matters more for engines that run on premium. Gas that doesn't have ethanol in it to begin with is ideal, as it doesn't need detergents to counteract the damage ethanol does (it's corrosive and wears down rubber/gaskets as well as creating residue/sludge in the engine). If you got ethanol free gas, it wouldn't be "toptier" because it wouldn't have detergents. However, you do raise a good point about the effectiveness of marketing jargon. The labelling of "premium" is another applicable example. A car deisgned specifically for 87 will get no benefit from 91+, it's just a waste of money, and yet many consumers think it's better for their car because of the name. For cars designed for 91+, that's different. The Stinger has a high tech engine that can run either, and using "premium" is more for a performance boost and better MPG.