I've been driving and racing cars for well over 20 years and while a tank of premium is good to burn out deposits I can't see it being worth while to run all the time since octane rating can't add ponies or MPGs unless the car has an optional octane can be used it shouldn't make a difference. 4th gen 4Runners had the option of running 89 or 91 with using 91 does generate beter acceleration with the V8.
'12 Focus Red Candy SE Sport 5 spd
'99 Toyota 4Runner Sport
'11 Subaru WRX STI Hatch