I had VMP write me three, 87, 91 and 94 tunes. That's what is available here for fuel. The tunes all make nice torque and power. I like the 91 tune best, because the 94 fuel here is full of additives that sap some of the zip you'd expect from the added timing allowed by the higher octane. The 91 adds timing as KR is not detected so the performance ultimately is the same but with the added zip down low from less additives. 87 is a little softer up top but performs like the 91 potting around.
I'm on auto and that's why I chose VMP; I'd say they are in the top 3 of folks that get how the auto works on this car, tune-wise.
I'd say you aren't really going to save alot running an 87 tune all the time, unless you're doing a 100 mile commute each day. You won't get better fuel economy from running lower octane necessarily, either.
2014 Premium GT, SGM, Brembo, Auto, Tech, Comfort, etc. GT500s, Steeda UCA, VMP auto tune, 100 shot on BBR tune, best et: 11.38 at 120.85
2012 GT, Candy Red, Brembo, 3.73, Tech, Comfort, etc. Procal tune, Roush upper, UMI LCAs, Steeda red bracket, GT500s, 28X10X16 Hoosier slicks, best et: 11.91 at 115.23 RIP