well I gues all this answers my the question that has been pondering me for years.

so I take it AMPM is ok then?

 

all the fuel comes from the same pipeline. the gas staions in new jersey were trying to save money so the owner was going out and putting water in the tank himself and he ended up paying for all the cars that got messed up. it caused alot of damage. there is regulation of how watered down the fuel can be for the octane rating and being all the fuel comes from the same place it only matters on the octane you use and if the gas station is reputable..... i use hess 93

 

or someone who works at a refinery.

here in memphis, all the stations get gas from the local valero refinery. so its all the same. however, shell does ship in their own supar-sekret 93 octane premium gas or whatever.