93 tune with 92 octane + 104 octane addative?

[plent]

Hey so im new with tuning and here where i live we only sell up to 92 octane. The tuner i just got only comes with a map for 87 and 93 which im running the 87 right now and that was a bit of a step from stock. would there be an issue if i use a additave to get to 93? i only ask since ive got no normal way to hit the 93 octane otherwise. if it helps its a 99 mustang gt with a few light mods. i can try to plug the tuner in to get the specifics for it but it didnt come with the computer connector so itll take a bit.

[mikel]

you should have a 91 octane tune that might be a better choice.