AMG chief Ola Källenius and engineering director Tobias Moers are showing us a lightly camouflaged new Mercedes-Benz S63 AMG. It's a long-wheelbase example with 4Matic -- a first for the S63. A short walkaround reveals other details. The exhaust can now play two different tunes. The battery is a tiny silver box stuffed with lithium ion energy cells -- it weighs 44 pounds less than the S500 battery. Peeking out from behind the optional twenty-inch wheels, shod with 255/40 (front) and 285/35 (rear) footwear, are carbon-ceramic brakes with massive, 16.5-inch front rotors. "All in all, we managed to reduce the weight by 220 pounds," says Moers. "All body panels, the roof, and the entire front-end structure are made of aluminum."
Inside, too, the S63 looks decidedly sportier than the plush standard S-class, with reshaped seats, perforated nappa leather, an IWC clock, larger shift paddles, a two-spoke steering wheel with a thicker rim, unique graphics on the virtual speedometer and tach, and plenty of AMG badging. Of course, the standard car's Burmester stereo, fully electric first-class rear seat with energizing hot stone massage, and host of driver assistance systems are available here too. North America gets only the LWB model, so that means standard 4Matic but no Magic Body Control; instead our S63 uses the AMG Ride Control sports suspension with Airmatic and adjustable dampers.
Time for a quick spin. On a quiet straight road, Ola Källenius holds the car with his left foot on the brake, turns the Speedshift selector to Manual, dials up ESP Sport, then floors the throttle. The S63 lunges forward, spinning its rear wheels ever so slightly as it gains momentum, the exhaust barking angrily to mark the split-second upshift into second gear, and then we are picking up speed and noise and flies and excitement again. The sprint from 0 to 62 mph takes only 4.0 seconds (4.4 seconds in the RWD version). Redlined at 6400 rpm, the 585-hp 5.5-liter twin-turbo V-8 makes its maximum torque of 664 pound-feet available from 2250 to 3750 rpm.
Driver change. Now it is Tobias Moers who turns the Affalterbach hinterland into his own private Nordschleife. "Although the power output went up by 41 hp, the real-world fuel economy improved by five percent," he claims. "With this rear-biased AWD system, the S63 AMG can now be driven with almost the same verve as the SL63 AMG. To push out the handling and roadholding envelope even further, we developed an uprated front axle, a variable-ratio sports steering, and a choice of two different chassis settings." Watching Moers put the S63 through its paces is a real eye-opener. Turn-in is immediate; grip is astounding even on broken pavement; the ESP's Sport mode permits small sidesteps but never deviates from the chosen line; and the carbon-ceramic brakes let you peep a couple of car lengths past the apex without punishing you for your curiosity.
And there's more still to come. An even more extreme S-class AMG is being readied for a mid-2014 introduction. Again badged S65, it will be powered by a tweaked V-12 engine that produces 635 hp and 738 pound-feet of torque, which should be more than enough to make the rear tires scream for mercy.