Nope, never used it. I've used the 89 a couple of times. My Predator gives instructions to run a couple of tanks of higher octane through before changing the tune to make sure that you really are running the full octane that it requires and not a lower octane mixture. When I read that, I took it to mean that their performance tunes must be on the hot side so I've just never taken the time to do it.
485mi @ 27.5g = 17.6mpg I've NEVER gotten that good w/ 87 even when I would light foot it. i even got on it a few times and still got that good. i'm keepin it light driving this tank, and i'll show ya my TRIP when it breaks 500 w/ still some "_ until Empty" in the tank still.
I flushed out everything with 93 octane and installed the hot tune on the truck. I won't be getting any better gas mileage for a while. I can't keep my foot out of it now.
Just keep the tune and you'll go back to your normal driving and see the benefits then. I figure, even though I am spending an extra $6 per tank to fill up, i'm still saving money over the year. (using $100 for a nice even number, plus thats almost what it is right now) 81 fillups of 87 = $100/fillup = $8100/YR in gas! 73 fillups of 93 = $106/fillup = $7738/YR Thats an extra $360/YR that I can do whatever w/. Just showing more numbers for benefits...