This is awesome! However, folks there may be a few problems with your solutions. A gearing change would likely result in lower fuel economy all around. If it drops too low you will have to pay a GG tax. You have to pay to play.
My guess is a revised intake, tune and exhaust system.
Also, one thing about that C&D test? They tested another Mustang with the summer tires (not the "all season" tires) and it ran a 13.0 flat at 111. Basically they picked the slower time of the two. The Mustang simply has an advantage in most cases, lighter with just as much power to the wheels.