2017 Ford Mustang GT by GME Performance

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.

A 705-horsepower Mustang reads like a spec-sheet flex until you notice who built it. This one did not come from a Californian shop with a marketing department and a magazine relationship, or from one of the German tuners whose names Americans already recognize. It came from a firm most enthusiasts outside hardcore tuning circles have never heard of, working out of a city better known for trade fairs than for muscle cars. That is exactly what makes the build worth examining, because a shop with no reputation to coast on has to get the engineering right rather than just the headline number. And the number here is aggressive enough that it lands in the same conversation as engines Ford and Dodge spent enormous budgets developing.

The Numbers Behind the Hellcat-Level Claim

GME Performance, based in Leipzig, built its 705-horsepower Mustang around an Edelbrock supercharger kit paired with a new intercooler, upgraded fuel delivery, and a stainless steel exhaust system with driver-controllable volume valves. The finished package produces 590 lb-ft of torque, which represents a jump of roughly 270 horsepower and 190 lb-ft over the Mustang GT’s stock 435-horsepower 5.0-liter V8. The 0-62 mph time falls to 3.9 seconds, the better part of a second quicker than the factory figure for a stock European-market GT. That is supercar territory for a car that began life on a Mustang GT order sheet.

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Why Germany Builds So Many Modified Mustangs

The German context matters more than it might appear. The S550-generation Mustang was the first to be engineered as a genuine global car, sold through Ford dealers across Europe with factory right-hand-drive availability, which put large numbers of them into a market with a deep and highly regulated tuning culture. Germany has no shortage of firms building Mustang packages, from Geiger Cars to smaller operations like Schropp Tuning, and they compete on engineering credibility because the certification environment there does not reward shortcuts. A shop selling a 705-horsepower conversion in that market has to answer questions about brakes, cooling, and emissions that a mail-order kit never faces.

The Edelbrock Route and What It Trades Away

The choice of an Edelbrock supercharger is itself a decision with consequences. A supercharger kit built around an existing, well-supported platform gives a tuner known airflow characteristics, proven intercooling, and a calibration starting point, which is why so many high-output Coyote builds start there rather than with a custom turbocharger arrangement. The trade is that a positive-displacement blower on a stock long-block is running the factory internals well beyond their design brief, which is why fuel delivery and intercooling upgrades appear alongside it rather than as afterthoughts. GME addressed both.

Power Without Forgetting the Chassis

Credit where it is due, the shop did not stop at the engine bay. The build includes an adjustable coil-over suspension, 21-inch alloy wheels wrapped in low-profile tires, and floating brake discs with their own ventilation system to manage heat under repeated hard stops. The aerodynamic package adds a front spoiler, side skirts, an underbody diffuser, and bootlid trim. Individually none of those are exotic. Collectively they describe a shop that understood a 705-horsepower car needs to stop and turn as convincingly as it accelerates, which is a distinction that separates serious tuners from dyno-chart merchants.

Twenty-One-Inch Wheels and the Ride Quality Question

The 21-inch wheels are the one choice worth arguing about. Larger diameter wheels with correspondingly shorter sidewalls look right on a car like this and improve steering response, but they add unsprung mass and reduce the tire’s ability to absorb road imperfections, which on a coil-over-equipped car can make an already firm setup punishing on real roads. Buyers chasing lap times generally prefer a smaller wheel with more sidewall. Buyers chasing presence at a car meet prefer the twenty-ones. This build clearly knew which customer it was for, and there is nothing wrong with that as long as the choice is made deliberately rather than by default. The floating brake discs suggest it was.

Where 705 Horsepower Sat Against the Factory Cars

For perspective on where 705 horsepower landed, consider what Ford was selling at the time. The Shelby GT350 produced 526 horsepower from its naturally aspirated flat-plane 5.2. The supercharged GT500 that would eventually arrive made 760. Dodge’s Hellcat Challenger sat at 707. GME’s conversion therefore put a standard Mustang GT within two horsepower of a Hellcat and comfortably past anything with a Shelby badge available at the time, for the cost of a supercharger kit and installation rather than a new car.

Tuner Mustangs Versus Factory Shelbys on Resale

That comparison also explains the one genuine drawback of the tuner route, which is resale. A factory Shelby carries a VIN, documented production numbers, and a warranty history that collectors and lenders both recognize. A tuned Mustang GT, however well engineered, is worth what the next buyer believes about the quality of the work, which means documentation becomes the entire ballgame. Receipts, dyno sheets, the calibration record, and evidence that the supporting modifications were done alongside the power are what separate a premium sale from a discount one. The same 705-horsepower car can be worth substantially more or substantially less depending entirely on the thickness of the folder that comes with it.

What This Build Still Teaches Ten Years Later

A decade on, the lasting lesson of this build is not the horsepower figure at all. Plenty of shops have since pushed Coyote-powered Mustangs well past seven hundred horsepower, and the number no longer turns heads the way it did. What still holds up is the completeness of the approach: a firm with no marketing budget and no household name chose to spend money on brake ventilation, adjustable damping, intercooling, and fuel delivery rather than on a bigger pulley and a louder press release. That is the difference between a car built to survive being driven hard and a car built to survive a dyno pull. Anyone planning a forced-induction build on a modern Mustang today would do well to copy the order of operations rather than the specific parts list, because the parts have moved on and the priorities have not.

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