2000, ford, mustang gt

U7146 predator

i got a predator ,
i heard you can choose what octane for what your car will run on,
how do i do that?

alright,
thank you for your help.

in 2nd gear i shift around 6500 rpm into 3rd
it just dont want to pick up in 3rd it's slower than what it should be.

2000 mustang gt
it's manual
but my question is
my 3rd gear isnt as fast as it should be when i shift into it,
1st will be fast 2nd will be fast 3rd is sloww
4th gear is almost as fast as 3rd
but
is their something i can do with the predator to make 3rd gear faster?

thank you.

i need a cord that connects to my computer do you sell them seperatly or can i get one from bestbuy?