Hmmm. I have to disagree. Most all of the gas comes from the same place. The refinery in NJ sells to all the major chains, BP, Shell, Exxon etc.. It is the same gas, just going to different dealers. Secondly, you never get 100% tier 1 or super because most pumps run all three grades through one hose. The hose is about 1 1/2 inches ID and 12-15 feet long, thats a lot of fuel (which the last user got regular) and at least 1-2 gallons will be mixed into. And my final 2 cents, Tier one or super is actually less powerful (explosive) than regular. It has an added retarding agent which allowes it to reduce knocking and pinging by delaying or lessening the possiblity of early detonation. The retarding additive makes the fuel less combustable therefore (my assumption) reducing the energy it can produce. Anyone out there working in a refinery should be able to confirm my belief.