In my '92 Civic I used the super from Shell, Chevron, and Exxon 92 octane. I've gone to the cheaper places, and really could tell no difference in performance, and I rarely checked the mileage. Once in a while I put in a bottle of Techron additive in to keep the engine running smooth. That has helped immensely. On my '04 Accord, I still use the super stuff.