Waiting for us on the cobblestone center court of AMG headquarters in the Stuttgart suburb of Affalterbach is a gunmetal gray Mercedes-Benz C63 AMG. Like its two direct competitors, the Audi RS4 and the BMW M3, the new top-of-the-line C-class is powered by a V-8. And like the formula favored by those cars, the latest DOHC four-valve is a high-revving, normally aspirated engine: it is redlined at 7200 rpm and delivers 451 hp at 6800 rpm. The smaller V-8 fitted to the 2008 M3 (page 64) can muster an extra 1200 revs, but it maxes out at 414 hp. Where the C63 has its biggest advantage, however, is in torque. Its bigger engine distances the pack with 443 lb-ft at 5000 rpm, followed by the RS4 with 317 lb-ft and the BMW with 295 lb-ft.
The C63 AMG is fitted with a seven-speed automatic, coined Speedshift Plus, that offers three different driving modes. C stands for comfort, and S indicates sport. The sport mode cuts shift times by 30 percent, triggers automatic downshifts on the approach to corners and descents, and blips the throttle, Ferrari-style. The purist should dial M for manual. In this position, gear changes are executed--wham, bang, go!--50 percent faster than in comfort mode. As you flick the steering-wheel-mounted paddles from one ratio to the next, you're aware that this is one of the quickest automatics on earth. The impending redline is reflected not only by the increasingly thunderous engine note but also by the digital display that changes color from amber to bright red. For the first time, AMG has developed a unique front suspension for the high-performance C-class. The new triple-link system is 1.4 inches wider. Wheel hubs and mounting points have been redesigned, torsional rigidity doubles, and steering accuracy and response are greatly improved. Stiffer springs, sport-tuned dampers, and a larger antiroll bar helped AMG engineers optimize braking performance, lateral acceleration, and stability. The steering rack was repositioned for more direct action, and a quicker ratio enhances turn-in and feedback. The brakes do without composite discs, but they boast extra-large rotors clamped by six-piston front and four-piston rear calipers.
From all angles, the C63 AMG looks decidedly more like a gung ho street fighter than a subtle stealth sedan. Changes from the stock C-class include a new front bumper with three large air intakes and a pair of foglamps, a hood with two power bulges, painted and polished eighteen-inch five-spoke wheels shod with 235/40 and 255/35 tires, a restyled rear apron with three diffuser fins, four chrome tailpipes, and a small spoiler mounted on the trailing edge of the trunk lid.
Inside, the C63 sports excellent bucket seats with integrated head restraints and adjustable side bolsters. A special AMG submenu in the instrument cluster can be set to display oil and water temperatures, the current ESP setting (on/off/sport), or the race timer. It's a functional and well put together driver's environment, but the materials still lack that special touch of class.
While both the BMW and the Audi engines are handicapped by their relatively modest displacements, the 6.2-liter AMG engine actually had to be detuned for the hot C-class, where it delivers 451 hp instead of 507 hp in the E63 and 518 hp in the S63. The extra power it musters over the RS4 and the M3 yields an acceleration advantage that is particularly obvious above 100 mph. Here, drag challenges every single horsepower, and the Merc benefits from its close-ratio, seven-speed transmission and its richer seam of torque, which helps to keep up the momentum. Mercedes says that the C63 AMG has been timed at 4.5 seconds in the run to 62 mph --quicker than both the BMW and the Audi.
With ESP set on sport, every empty on-ramp triggers a smile. With ESP off, the C63 AMG qualifies as a hooligan's delight, but this doesn't mean that it's constantly struggling for traction and composure. How does it differ from the M3 and the RS4? In the Audi, you need to have courage to do sideways stints in the dry. In the BMW, power oversteer is still very much part of the DNA, but the transition from hang-on to let-go is not as creamy as it used to be. The Mercedes, however, further elevates the level of adhesion, and when it senses that the driver wants to play, it plays along. Earlier AMG models were initially less forthcoming, but when they did throw in the towel, the rear tires typically went up in smoke. The C63 has new ESP software that reduces wheel spin without deflating the expressive cornering attitude.
The 3814-pound C63 AMG decelerates extremely well. Everything about these brakes is spot-on: the initial feedback, the relentless energy-squashing bite when you put your foot down hard, and the ability to quickly scrub off triple-digit speeds, again and again.
There is really only one area where potential owners should be prepared to make compromises, and that's ride comfort. Most AMG products this side of the CLK Black Series have surprisingly compliant suspensions, but the C63 AMG does not. It employs firm dampers and very firm springs, so expect to feel every surface detail. Even the M3 rides better than the C63.
Overall, the C63 has impressive attributes that you don't expect from a Mercedes--agility, driving pleasure, balance, chassis, steering, transmission, performance, value for money. With this new C-class on steroids, the gentlemen from Affalterbach have created a very convincing automobile. We put the car through its paces for eight hours and 250 miles, during which the C63 soared from underdog to overachiever.