Hodna recommends using a gasoline with a detergent... whatever that means. I use Chevron because of the Techron. I don't know if others use similar additives, but they did a pretty good job of marketing it! I'm not 100% sure it's anything more than that, but it works for me.
Any major brand, and surely most lesser brands, has adequate detergent additives. The days of gasoline without detergents has largely passed from what I understand. The owner's manual says a minimum octane of 86.
Having been in the transportation biz for some time, I can assure you that it all comes outta the same horse. Octane is really all that matters.
Tankers frequently are rerouted to different stops, and a load that was destined for Mobil and had their additives added will wind up at Hess, or 7-11 or Shell. The days of these companies being able to isolate their fuel is long past.
Regarding any Gas Retailer using only domestic product, I would be hard pressed to believe it. They swap inventory on paper on every city they serve.
They dont care where it came from as long as the wholesale $ is right.