Originally Posted by Bimmer Nerd
Basically you are saying that it doesnt matter if i get 91 from arco vs shell because its essentially the exact same thing ?
Well not per say. If you compare Shell specifically they have their own additive but that too is a very miniscule amount. A fair comparison would be Arco's 91 to another "low end" gasoline brand.
With that said, there isn't as much difference between gasoline as people think (based on respective octane)