To understand why Mercedes-Benz calls the 2007 S65 AMG the “world’s quickest four-door,” you need to know just two figures: 604 horsepower and 738 lb.-ft. of torque. With it’s hand-built, twin-turbocharged, 6.0-liter V12 engine firing under its sculpted hood, the S65 AMG rockets from rest to 60 mph just half a click slower than a Corvette Z06, at 4.2 seconds. The sad thing is, most S65 AMG buyers will want it because it’s the most expensive S-Class in the stable, and not because they actually plan to drive the thing.

And that means the engineering expertise that goes into this motor is lost on most S65 AMG owners. Stuff like a precision-balanced crankshaft with a longer stroke, larger-bore forged pistons, and upgraded oil-spray cooling and bearing lubrication systems. But we’ll bet that if friends and family want to pop the hood, they’ll be impressed that the single AMG engineer who build it, from start to finish, also hand signed it.

Other upgrades that turn a regular S600 into a 2007 Mercedes S65 AMG include high-performance two-piece brake rotors squeezed by stout eight-piston calipers. Mercedes claims that this compound rotor design saves weight by 20 percent over conventional systems. Helping to haul the Benz down from speed, those front discs are internally-ventilated, perforated, and measure 15.4 inches in diameter. In back, the S65 AMG is equipped with 14.4-inch discs clamped by four-piston calipers. ABS and brake assist are standard.

The suspension gets a massage, too. The standard S600’s Active Body Control (ABC) suspension uses AMG-specific spring struts with firmer damping for sportier ride quality and improved handling. ABC reduces dive, roll, and squat through the use of hydraulics, electronics, and mechanical parts, normally reducing roll by 68 percent. A switch on the console directs ABC to scrub lean by as much as 95 percent if the driver wishes. Mercedes also revised the traction and stability control systems so that they behave commensurate with the S65 AMG’s performance potential.

Those are the changes that can’t be seen. To make sure everyone knows you’re driving the baddest Benz on the block, staggered-width twin-spoke wheels are added, wearing 255/35ZR20 performance tires in front and 275/35ZR20 rubber in the rear. Yep, that means this is the first Mercedes to get factory-installed 20-inch wheels. The 2007 Mercedes-Benz S65 AMG also gets a unique front fascia with larger air intakes and clear-lens fog lights, AMG-specific side skirts, and special rear valence panel treatment punctuated by twin chrome exhaust outlets. The result is subtle, except to those in the know. For the common folks, chrome “V12 Biturbo” badges on each front fender announce the S65 AMG’s exclusivity.

The S65 AMG’s cabin gets the full leather treatment, including the dashboard pad, which is also trimmed in burl walnut or chestnut wood. The AMG-specific performance seats are heated and ventilated, and the car includes pneumatic door and trunk close assists. Safety gear mirrors the new 2007 Mercedes-Benz S550 and S600, including dual-stage front airbags, side-impact airbags in each door, and side-curtain airbags.

Expect to pay a pretty penny when the 2007 Mercedes-Benz S65 AMG goes on sale later this year, but when it comes to high-end Benzes, price is a moot point.

Photos by Ron Perry