you would also need a new center section that can accept 31 spline axles. keep in mind that he 05 mustang gets 31 splines. the reason that teh stock stangs use 28 spline is because thats what most people ever need. there are thousands of people who own mustangs, gt's, mach's and cobras included that have never, and never intend to race it, they just want a car that looks good.