The 4.0-liter V-8 for the first time is fitted with a pair of twin-scroll turbochargers, resulting in 563 horsepower and 553 lb-ft of torque in the basic, non-S model. The sprint from zero to 60 mph takes a mere 3.4 seconds, according to Mercedes, and top speed is limited to 155 mph. In the E63 S, engine output reaches a new high of 603 horsepower and 627 lb-ft, the latter delivered on a plateau that stretches from 2500 to 4500 rpm. The S reaches 60 mph in a factory-estimated 3.3 seconds, with its top speed capped at 186 mph.

But the engine also is more efficient, thanks to an all-new cylinder-deactivation system that shuts off cylinders 2, 3, 5, and 8 at low-to-medium loads between 1000 and 3250 rpm. Turning a V-8 into a V-4 produces less noise and vibration than turning off one cylinder bank.

A nine-speed automatic is standard (we can’t imagine it could ever want for more gear ratios), and the transmission eschews a torque converter in favor of a wet starting clutch. Once through the gearbox, the increased torque is transferred to the road via an entirely new all-wheel-drive system called 4MATIC+, which features variable torque distribution. The system can be tweaked to send 100 percent of the engine’s torque to the rear wheels—yes, all the time—via the selectable Drift mode. A standard feature on the S model (and optional on the regular E63), Drift mode is accessed in the Race drive setting, with the transmission in manual and the stability control switched off.

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