[tossass4370]

For the S197 08/09 Bullitt, the OEM tune is adapativeable with varied octanes as it has a knock sensor. So you can run 87 to 93 octane and the tune will adjust. And the 08/09 Bullitt was Ford's first with an OEM Cold Air Intake.
So for an occasional or daily driver with no engine external mods beyond underdrive pulleys, throttle body spacer or air filters, the OEM tune is GREAT.