The 2014 Mercedes S63 AMG 4Matic is faster than a Porsche 911 Carrera S.

So what happens if you try to improve on the “ultimate” premium luxury sedan, a term one hears from the folks at Mercedes-Benz when discussing the new 2014 S-Class?  The answer appears to be the upcoming Mercedes S63 AMG 4Matic.

Churning out 577 horsepower, enough the launch the Teutonic tank from 0 to 60 in just 3.9 seconds, the S63 AMG model adds yet another level of performance and technical sophistication to a new-for’-14 S-Class that already boasts some serious cajones.

Meanwhile, the addition of the 4Matic designation highlights the German maker’s recent announcement that virtually all of its future AMG models will come standard with all-wheel-drive — the rare exceptions including the Mercedes-Benz SL roadster and SLS supercar.

The heart of the beat: a 557-hp, twin-turbo V-8 paired to a 7-speed Speedshift gearbox and 4Matic AWD.

The all-wheel-drive system will be mated to a hand-assembled biturbo 5.5-liter V-8. The most powerful member of the Mercedes’ M157 engine family, it makes some enviable numbers, the 577 horsepower noted above and 664 pound-feet of torque. For comparison’s sake, that’s up from “just” 536-hp and 590 lb-ft in the outgoing Mercedes S63 AMG.

As a colleague noted, the 3.7 second launch is slightly faster than a Porsche Carrera S — and with a limited maximum speed of 186 mph, the big Benz also has a higher top end.

(2014 Mercedes-Benz S-Class is a technical tour de force. Click Here.)

Credit a variety of updates to this example of the M157 V-8, such as those twin turbos, an air-to-water intercooler, piezo fuel injectors, four valves per cylinder with camshaft adjustment and more.

The new S63 also adopts a Stop/Start system – like the rest of the new Mercedes-Benz S-Class line-up – that automatically shuts down the engine at idle and then fires it back up when the driver’s foot lifts off the brake pedal.

As with the "base" Benz S-Class, the interior is a lavish place to relax, drive or work, especially in the high-tech/high-touch back seat.

The German maker also claims to have shaved 220 pounds off the weight of the AMG performance model through such things as special forged light-alloy wheels, a special two-piece brake design and a new lithium-ion battery.

(Mercedes will reveal new S-Class Plug-in Hybrid at the 2014 Frankfurt Motor Show. Click Here for details.)

As a result, it significantly improves the power-to-weight ratio, now an impressive 7.9 pounds per horsepower.  But the combination of an improved combustion system, Stop/Start and lightweighting also adds up to improved fuel economy, Mercedes claims – though it isn’t ready to release final numbers on any of the 2014 S-Class models, including both the S63 AMG and the more mainstream S550.

The twin-turbo V-8 delivers plenty of fury, but it’s also designed to add in the sound to go with it. The S63 AMG 4Matic adops a new “logic-controlled exhaust flaps” system, that mutes the powertrain during most situations, and especially when the transmission is operating in C, or “Controlled Efficiency,” mode.  But shift to Sport or Manual modes and the exhaust flap flies open at the first chance during aggressive driving, resulting in what Mercedes describes as “an even fuller, emotional hallmark AMG engine sound.”

The transmission, incidentally, is AMG’s own 3-mode, 7-speed MCT Speedshift.

The new S-Class is a high-tech tour de force, and the AMG model only ups the ante.

As with the “base” S-Class, if one can use such a term, the S63 features a veritable explosion of technologies designed to improve safety, comfort, performance and handling. The S63 model comes stock with an AMG Adaptive sports suspension. It’s a higher-performance version of the new Mercedes adaptive air suspension which uses stereo cameras mounted behind the rearview mirror to scan the road ahead and instantly adjust suspension damping to make harsh bumps and potholes virtually vanish.

In AMG configuration, the adaptive system has been optimized, Mercedes explains, to enhance “the vehicle’s agility when driving dynamically.”

Other AMG enhancements include an electromechanical speed-sensitive sport steering system featuring a variable steering ratio. In Sport mode, it delivers more direct feedback, especially when launching aggressively through corners. Meanwhile, the ESP Curve Dynamic Assist system uses “targeted brief brake intervention” to direct torque to the outer wheels to reduce understeer.

The 2014 Mercedes-Benz S63 AMG 4Matic will make its official world debut at the Frankfurt Motor Show in September – the same show where the maker plans to unveil a new plug-in hybrid version of the S-Class. The AMG edition will reach U.S. showrooms in November. Pricing and fuel economy numbers are expected to be released shortly before the start of sales.

(Hyundai hopes “value” pricing of 2014 Equus can take on premium-lux leaders like the new S-Class. Click Herefor the review.)