Octane options and 91/93 tune files

If you get a 91 tune, and use 93, you'll see like 2/3HP more lol. The difference is that the tune will perform optimally across a range of conditions, whereas if you get a 93 tune, and run 93 100% of the time, whenever you're in inclement conditions or at altitude the engine will still pull timing despite being tuned for the octane you're using. Just think of it as being more consistent, running 93 on a 91 tune. Conversely, running 91 on a 93 tune, will show tons of timing pull, across the rev band. You'll put down less power running 91 on a 93 tune than running 91 on a 91 tune.

^That's why I run 93 plus 3 gallons of E85 on my stage 2 93 tune