JSC-Thanks for the link on "top tier gasoline". I always wondered if there was really a difference in additives and this answers my question. The current list adds some additional brands including Texaco and a couple I have never heard of. "The Fridge" (08 S5, Ibis White, loaded) just finished a 5800 mile road trip and I did notice some subtile (and not so subtile) differences in performance in different parts of the country.
