yeah the file is meant for 100 octane. odds are if you use 93 the computer will notice it and pull timing right away, not resulting in any damage, but dont chance it.

 

^this...

The higher the octane, the less chance of detonation. In race gas mode, the timing is advanced to take advantage of the less chance of detonation. Having the timing advanced that far while using 91/93 (whatever is in your region) could be bad for your engine.

 

Don't qoute me but I believe valet mode won't let the motor go over 4k rpms. Have you ever seen Farris buehler? When the valet driver guy takes the car out on the town. It'll prevent that from happening! Chica Chicahhhhhhhh ohhhhh yeeaaaah! Or if you don't trust a mechanic.