Best tune for best MPG
So I have had my SCT tuner for almost a month now and have been playing with the different tunes, testing them out, comparing. I am trying to figure out which tune to use for best fuel ecomony for a long trip ( and then switch to the Race tune for crusing). So in your experience, which tune has given the best MPG; street, Performance, Race and also which octane. I would expect the 91 octane would give best results since it has more energy than lower octane. Thanks for your help!
2009 Vista Blue Mustang GT manual with 10" white racing stripes. C&L street CAI, SCT tuner with 91 Race tune. 14" antenna, 2010 mustang gt "belly pan", sequential tail lights, Hurst billet competition plus shifter, Borla ATAK catback exhaust, Kooks LT headers with Catted H pipe, mid-mounted dynomax race bullet mufflers (as resonators)