I work in the gasoline trading business. Think boats moving from refineries across the world, moving on pipelines...etc. 99% of all the gasoline you put in your car is exactly the same. It exchanges hands so many time, Equnior's product will become Exxon's product which will become Shell's product which then will become BP's product which then will become a trader's product which then will be put into a tank farm which all the gas station in the local area will load their local tanks from. IF it's bad gas (which does happen on occasion) it's not the 'brand' that has bad product, it's likely the local owner who's watered down the product to maximize his profits. Moral of the store is all the gas your buying is coming from the same refinery, is blended by the same people, and shipped & delivered by the same people. The non branded fuel 99% of the time is coming from the exact same tanks the branded product is coming from. Now the real question is do you trust the owner of your station to not water down the gas?
Always thought the only difference, besides budget leaky tanks, was what was added prior to delivery ie proprietary additive that are different in a Shell v a Mobil product for example. Octane, by law, is definitely different unless the crooked stations play with the blends beween 87 & 89. 89 is the total waste of space on a pump.
2018 Alfa Romeo Stelvio TiSport EC Phase 2 w/V2 intake, Remus Catback ~390HP / 442ft-lb Tq Visconti Verde, Chocolate Interior, Quadrofoglio wheels w/PZ4's
2016 Maserati GranTurismo Sport Custom blue tone, Grigio chrono leather w/full interior MC Carbon Fiber trim, NA 4.7L Ferrari V8, stock...for now
2016 Range Rover Sport HSE 3.0SC tuned by ETG 456HP/414Tq, Montalcino Red, Ivory
2012 Maxda MX5 Miata GTPRHT True Red, Black
2011 Lotus Evora S Persian Blue,Black Suedetex (Track specialist)