^ What he said.
I'm not personally familiar with SCT, but assuming that it's menu operates similar to Diablo you would just go to a menu option like Modify Parameters which will then bring up a list of things such as axle ratio where you can make changes as appropriate. Read through the owners manual on the device (download one from the manufacturer site if it's missing), it should walk you through this. If you can't figure it out and you originally bought the AM/Bama tuner deal then just contact them and they can get you set up.
2001 GT Convertible
8 cylinders, 5 gears, red.
6 cylinders, 3 gears, also red.
Remember my motto kids: Be bitter, stay angry and blame everyone. It's on my fridge magnet!