If you don't have an aftermarket stall converter and a jmod/shift kit then I wouldn't bother. Not going to do anything for you. Even if you do get that stuff, the computer can still shift faster and more accurately than you can.
Also don't buy from AM. Buy from almost literally anywhere else.
2000 Mustang GT Steeda #0048 34k miles. 99 Cobra 4V swapped, FTBR IRS swapped, exhaust, tuned by James Gordon.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.