Although I don't have a custom tune I fill up with QT gas almost 90% of the time. I get great gas mileage, usually averaging 22-23mpg on normal driving highway/city. I too stay away from Shell, one because its so damn expensive, and two because of the things Tim and Josh are talking about.
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Airaid CAI | Borla S-Type Catback | Amsoil 10w30 and MTG Trans. Fluid
382hp 387ft/lb | 1/4: 12.9 @ 112mph
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