I have a stock 2007 GT and plan on adding the steeda intake with a custom tune using the XCAL 2. I live in Cali and the highest octane we have is 91. Is this the best route to go for with the tune? and am I going to loose or gain in gas mileage as apposed to 87 octane with the stock tune?

 

You should see a little better gas mileage as that setup will lean your a/f a bit, but it probably won't make up for the added cost of the premium.

The ONLY way to know for sure would be if you were to document the change in the a/f on a dyno.

 

Good advice, thanks.

 

with a tune and intake you should see i would hope a bit better mileage but more importantly more power. You should be able to tell the tuner your getting the tune from that you live in cali and can only get 91.

 

will do, thanks.