GME Performance, a Leipzig tuning shop most American enthusiasts have never heard of, built a Mustang GT making 705 horsepower and 590 lb-ft, enough to put a stock Hellcat on notice. What separates it from the usual dyno-number flex is everything that came with it: adjustable coil-overs, ventilated floating brake discs, a full aero kit, and a 3.9-second 0-62 time. Read on for how the build came together and how it stacks up against Ford’s own factory answers.