I have not tried running a higher octane fuel specifically because my user manual for the tuner states to only use the fuel octane for specific tune. It's a 87 octane tune so consistently use 87 octane from the local Mobil station in town. I never vary from this station unless I am away from the area. I'd try a higher octane if I was sure it wouldn't cause any damage but like manual said it may result in damage. Will it really I don't know. May just be a way of c y a not too sure