although with the auto, you dont have to worry about shifting the right gears just put the pedal to the floor and drive like a bat outa hell but you wont have the initial acceleration or high end speed as if you would have with a manual. you wont get as good MPG as you would with a manual (taking you are going to drive the car on the streets and not gun every time). You are talking about making your car a drag, you got to match the drivetrain strength with horsepower and torque rating. If you are going to make the car put out close to 500 HP then i would suggest getting the TTC T-56 6-Speed Manual w/11in Clutch from the 04 mustang cobra. if you are going to make more HP than that then you should really invest in a strong and sturdy tranny or you would just be wasting money and time when you drop the tranny in the middle of the run.