throw on a 65mm throttle body, long tube headers and some nitto drag radials and run 13's all day long. i had a 03 gt with a saleen supercharger and every bolt on like you have and ran 12.7 it takes a ton of money to make the mustang run 12's but you definitley need some sort of drag radial on her to hook up on the launch. very torquey and easy to break traction with 3.73 gears. good luck

 

damn i cant believe i just waisted my breath