Today I found a gas station near my house that has 93 octane fuel. I didn't know this station had 93. I have a tune in my '06 GT for 91 octane, and don't want to change it, since 93 is scarce around here. Is there any advantage or disadvantage to running 93 octane fuel with a 91 octane tune?

 

Only advantage is your pretty much guaranteed that your getting at least 91 octane . I run some 98 octane with my 93 octane tune at the track just for insurance

 

93 isn't going to help you with a 91 tune.

If the 93 is cheaper then go for it... if not... don't bother IMHO.

 

Won't hurt and won't help.

 

It won't do anything for you, unless you decide to run a power adder and then it's just added insurance.

 

You can get a little extra power out of 93 gas if you bump up the global timing 2 deg., assuming you have a tuner. Just make sure to listen for any pinging.