On the outside the C63 Coupe copies the sedan from the A-pillar forward. The roofline is more raked, with roughly an inch-and-a-half lower profile. The C-pillar is thinner and the rear quarter windows feature a quick upturn at the rear similar to BMW's Hofmeister Kink. The new racy profile features a panorama roof that stretches back over the rear seats. Large pieces of motorized glass open up the rear space and may explain the weight difference between coupe and sedan. The roof represents and interesting contrast between the C63 and its closest rival, the BMW M3. BMW has chosen to go the performance route with a lightweight carbon-fiber panel, while Mercedes has clearly chosen luxury. This one feature may best sum up the differences between the two rivals.
Although the front and rear fascias are quite different for the 2012 model year, the average person may not realize they were redesigned on both C63 models. The front valance is now more aggressive, with a black front splitter at the bottom edge. To the sides of the splitter are inlet ducts capped with LED driving lights, while around the sides are air outlets similar to the outgoing model. The oversized Mercedes star floats in the grille on a single wing-shaped bar and adds an even more aggressive look than the standard C-Class Sport's two-bar grille. Above that, the new aluminum hood features redesigned AMG Power Bulges. The previous bulges ran straight front to back, but these take a decided angular turn towards the outside of the car three-quarters of the way back.
At the rear, Mercedes has kept the dual twin exhaust tips exiting each side of the rear valance. Between the exhaust tips is a larger, flat-black diffuser with three longitudinal fins. Both front and rear fenders are flared compared to the standard C-Class and the fronts are even wider than the previous version.
Mechanically, the AMG Coupe and Sedan are identical, powered by Mercedes' 451-horsepower 6.2-liter V-8. While these seem like realistic power figures for its class, the big difference between this and other German premium V-8s is the 443 pound-feet of torque. That's roughly 150 pound-feet more than BMW's V-8 M3, and 118 more than Audi's supercharged S4. For those needing yet more power at the top end, AMG is going to carry over the 30-horsepower Development Package. The kit consists of a lighter, forged crankshaft connecting the rods and pistons, helping to decrease engine inertia. Along with the extra power, two-piece front brake rotors are added and the top speed governor is moved from 155 mph to 174 mph. The package's only visual tip-offs are red brake calipers and an intake manifold painted in titanium silver.