Auto Dynamics has unveiled an extensively modified Mercedes-AMG C 63 S, code-named the Charon, and even though it looks relatively standard from the outside, it has a lot going on beneath the skin.

In stock form, the C 63 S is powered 4.0-liter twin-turbocharged V8 pumping out 503 hp and 516 lb-ft (700 Nm) of torque, making it more than fast enough for buyers looking for a performance sedan. Evidently, though, those figures were not enough for Auto Dynamics.

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The V8 has been equipped with the tuner’s AD850+ performance power package, which means that it rocks a pair of new turbochargers and new heat exchangers, a carbon fiber intake, a catback exhaust system with adjustable valves, a Weistech oil transmission pan, a Weistech VTA / BOV Adapter system and an ECU tune. These modifications result in an output of 843 hp and 716 lb-ft (972 Nm) of torque, meaning the tuned C63 S boasts an extra 340 hp and 200 lb-ft (272 Nm) over the stock car.

Other modifications include Eibach lowering sport springs, Fischer Stahlflex stainless braided brake lines, and satin black 20-inch BBS wheels wrapped in Michelin Pilot Sport 4S tires.

This unique C 63 S also includes the ‘AD Black Star’ exterior package that includes a blacked-out grille and unique yellow branding. Viewed from a distance, though, the car looks just like any other C 63 S.