The 603 hp version of the carmaker’s most popular model tames back roads as well as it tackles the track.Two rows of all-new E-Class sedans sat on the rain-soaked airport parking lot in Faro, in southern Portugal. Across the way, a large construction-company sign nailed to the wall of the terminal entrance proclaimed, “Great things are happening.”The slogan suits Mercedes-AMG, the high-performance division of Mercedes-Benz that in recent years has created some of the world’s fastest and most beautiful cars. One of them is the AMG E63 S Sedan, the top-of-the-line, most-powerful variant of the recently redesigned E-Class.Its capabilities and versatility are such that it can serve as an efficient, nearly autonomous commuter when it’s in Comfort driving mode or as a track-worthy performance car when it’s in Sport Plus mode. It will be arriving at U.S. dealerships this summer. Mercedes-Benz had not yet announced a price when Robb Report went to press.The car’s engine is a hand-built 4-liter biturbo V-8 fitted with a pair of twin-scroll turbochargers. It works in concert with a new 9-speed transmission that forgoes the traditional torque converter for a wet clutch. On the standard E63 (which will not be available in the States), the setup is good for 563 hp and 553 ft lbs of torque and enables a zero-to-60-mph time of 3.4 seconds. On the E63 S—the model that I drove in Portugal—the engine’s output is bumped up to 603 hp and 627 ft lbs of torque. The extra power reduces the zero-to-60-mph time to 3.3 seconds.A new version of Mercedes-AMG’s 4Matic all-wheel-drive system continuously varies the amount of torque sent to each wheel for optimal traction, while “drift mode” enables the sedan to behave like a rear-wheel-drive sports car. The E63 S is also fitted with the same autonomous technology as the standard E-Class. It enables the car to steer, brake, and accelerate on its own, as long as you regularly lay a hand on the wheel.Visually, the E63 S is distinguished from its tamer siblings by a front-end design that includes a more muscular-looking hood, wider fenders, a splitter, and the AMG sport grille with its integrated three-pointed star. In back, the E63 S is set apart by a deck-lid spoiler and a diffuser with integrated exhaust tips. The 20-inch AMG wheels are fitted with optional Z-rated performance tires; metallic bronze-painted calipers denote the optional carbon-ceramic rotors.The route from the airport to a racetrack in Algarve passed large luxury hotels that looked as if they had been uprooted from the streets of Las Vegas or Dubai and planted here among otherwise sparse environs. The narrow, twisting roads between the resorts proved an ideal setting for the car’s Sport setting.In this mode and the even more aggressive Sport Plus setting, the E63 S’s exhaust strikes a perfect balance between the mature rumble of the larger S63 and the lively crackle of the smaller C63.Matthias Schöttle, the chief engineer for the new E63 models, said that creating the right sound for the new family of turbocharged engines was initially a challenge. “We did a lot of engineering there,” he said. “At first it sounded like a fish boat.” Schöttle laughed and mimicked the sound of a sputtering engine. As the E63 S growled and backfired on its way to the track, the small herd of wild burros on the hillside looked on approvingly, or so it seemed.Arriving at the Autódromo Internacional do Algarve, a Formula 1 facility that hosts several international racing series, I hopped into another E63 S and, with a group of other drivers, followed Jan Seyffarth around the circuit. Seyffarth is a former pro driver whose credits include European GT3 racing. We had to push the cars hard just to keep up with him. When I put the hammer down on the front straight, the E63 S effortlessly hit 140 mph before I pressed hard on the brakes at the first corner. The gear shifts were imperceptible, and just as Comfort mode maximizes efficiency with the car’s nine gears, Sport Plus mode wrings out maximum performance without any drama.Here the fully variable all-wheel-drive system shined. As I drove the sedan over blind hills and through high-speed corners, the amount of torque sent to each wheel changed constantly. In a tight hairpin, for example, the system sends more torque to the rear wheels for maximum grip around the corner. When you’re coming out of the turn and onto the straight, it shifts more torque to the front for maximum exit speed.Mercedes-AMG is known for its impeccable interiors, and the E63 S’s interior is no exception. The front sport seats are equipped with adjustable side bolsters that keep even smaller drivers secure; some larger drivers may feel squeezed by them. Carbon-fiber trim with a glossy finish surrounds the classic round air vents, and you can set the cabin’s ambient lighting to any of 64 tints.“We’re really proud because there is so much new on the car,” said Schöttle, who posted the fastest lap time behind Seyffarth. He acknowledged that most owners will never take their cars to the track, but he and his colleagues are pleased to know that anyone who does won’t be disappointed.Mercedes-Benz (mbusa.com)Mercedes-AMG C63 S CoupeAnother recent addition to the Mercedes-AMG portfolio is the C63 S Coupe, the $75,000 high-powered version of the two-door C-Class. It conveys elegance with attitude, especially when it’s clad in the Edition 1 package. This livery mimics that of Mercedes-AMG’s DTM (German touring-car series) racecars. Bright-yellow asymmetrical racing stripes run the length of a body painted in Selenite Grey Magno, a metallic paint with a matte finish. Equally electric-yellow trim runs along the edge of the twin-spoke wheels—19 inches in front and 20 in back.The C63 S Coupe uses a version of AMG’s hand-built, 4-liter biturbo V-8 that produces 503 hp and 516 ft lbs of torque (469 hp and 479 ft lbs in the base C63 Coupe model). The coupe is at its best in Sport or Sport Plus mode, when the stiff chassis stays flat through tight chicanes and sweeping turns. The optional front carbon-ceramic brakes have fantastic bite; their short pedal travel inspires confidence going into the trickiest hairpin. The steering wheel is equipped with paddle shifters, but the 7-speed automatic transmission changes gears perfectly well on its own, accompanied by a delightful sputter here and there out of the twin tailpipes. In Comfort mode, the exhaust sound and the sport suspension become more subdued, transforming the C63 S Coupe into a daily driver, although even in the docile setting, the ride is firmly sprung.