Active body control gives this big, two-and-a-half-ton sedan the agility of a

Mercedes-Benz S65 AMG

Students of scoops, badges and other muscularity enhancement on cars will recognize the Mercedes S65 AMG as the most powerful production sedan on the planet.* For the majority of those who give it a passing glance, however, it will probably register as nothing more than a big, solid imported sedan. And that is all well and good. In this age of inconvenient truths, it's not necessarily desirable to flaunt having 604 horsepower to propel your regular complement of seats and a trunk over the highways and byways.

But for those who appreciate such things, this is a notably capable and sophisticated assembly of a trunk and seating for five. The latest edition of the Big Benz has more gadgets, gizmos and aerospace-inspired systems than you can shake a memory stick at. The owner's manual runs to 710 pages, suggesting it might be time for FlightSafety, the aviation training company, to consider diversifying into the automobile business.

This car offers everything from seats that behave like a fighter pilot's G suit and a night vision system to a moving-map display and intelligent autopilot. There's also an instrument landing (parking) system, in the form of a predictive backup camera, and EICAS (engine instrumentation and crew advisory system).

Then there's the engine itself. There's nothing quite like having a twin-turbo V12 at the beck and call of your right foot, poised to churn out 738 pounds-feet of torque at just 2000 rpm. I have not experienced such sustained, uninterrupted, synapse-tickling acceleration since being catapulted off the carrier USS Abraham Lincoln in the back seat of an F/A-18 (zero to 170 in less than three seconds). Even the brutally fast Corvette Z06, while quicker than this Benz from zero to 60 (3.6 seconds versus 4.2), cannot match the sustained and relentless lunge of the S65. In the Chevrolet, there is the fun of shifting manually through six gears, but that does make for a jerkier experience in high-energy bodily relocation.

And in the Benz, you can share the experience with three times as many passengers. After a maximum-effort dash to 100 with four aboard and immediate max braking back to zero, a friend in the back of the S65 AMG who has done his fair share of racing was reduced to blurting out, between guffaws of delight, enough "ohmigawds" to keep up with a car-load of teenagers.

My wife did not care for the brutal ride of the Z06, but she warmed to the more refined sensations of the S65, particularly its massage seats. This is a car that can thrill, please, mollycoddle or petrify all aboard.

Mercedes has long since outgrown its reputation for stark Teutonic interiors that offered only marginally more warmth than a bank vault. Open the doors of the S65 and a people capsule beckons, striking a welcoming balance between solidity, functionality and the creature comforts of curved wood, supple leather, soft liners and a roof-length moonroof. A friend of my son who, at six-foot-five, takes after his former New York Giant dad felt equally comfortable in the front or in the back with the front seat moved fully aft.

The array of systems in this car well complements the performance. Just as a G suit
exerts pressure on a fighter pilot's body to limit blood migration under G loads, so
do the side bolsters of the S65's seats inflate to work against lateral G during cornering. Turn left, and the right sides of the cushion and seatback inflate to counteract the centrifugal drift of the occupant toward the outside of the turn. The degree of inflation varies with the severity of the turn, and the effect is to virtually dissolve any lingering line between man and machine. Always thinking, this car; always looking out for me.

Slam on the brakes at any speed above 40 mph, and two unusual features kick in. One is the adaptive brake lighting, which pulses the brake lights with increasing urgency as you brake harder, to alert those behind that the car ahead has hooked the arrester wire, is stopping right now by clamping down hard on 15.4-inch-diameter front rotors (14.2 inches on the rear) and will shortly become a serious obstruction. The brakes are powerful, bringing this 2.5-ton car to a halt from 70 mph in just over 150 feet.

Once the S65 comes to a standstill under these emergency measures, the hazard warning flashers turn themselves on. They remain illuminated until the car has resumed a forward speed of at least six mph.

The adaptive brake lights are among several S-class features unique to the 12-cylinder cars (the S600 V12, packing a relatively pedestrian 510 hp and 612 lb-ft, is naturally aspirated and lacks the AMG tuning tweaks). Others are active head restraints (which move to beat whiplash to the punch in a collision), and automatic engine oil-level check and "add one/1.5/two quarts" advisories in the instrument display as appropriate.

Unique to the S65 AMG is a manual transmission shift program operated by steering-wheel paddles. On the instrument menu of both V12 cars is an oil temperature readout presented in blue until it reaches 176 degrees F, at which point it turns white and the driver is free to dig his spurs hard into those 510 or 604 horses. On the S65 AMG, electronics restrict power output at engine oil temperatures below 68 degrees F.

This is the second car we've critiqued here, and it presents the same dilemma as the Rolls-Royce Phantom in the last issue: These cars are so good that a review can appear to be unbalanced. Is this Benz perfect? Not in the Rolls sense of serene isolation and handcrafted opulence, but as a Bahn-burning driving machine with room for the family, yes, perhaps this is the perfect car-at least as of 2007. No doubt it will seem dated in five years if the horsepower, handling and systems wars of today continue unabated.

You can slice through corners in the S65 with an aggression that would defeat most sedans. I took my son out to lunch at his college in the S65, and as we approached the sharply curved off-ramp near the end of a bridge at a goodly clip, he quietly reminded me, as I thought he might, that we needed to turn off. The car thrust through the curve of the ramp with a sure-footedness more akin to a BMW M Coupe than the king of M-Benzes.

This is an agile and tenacious big car, thanks to active suspension, which places at each wheel a coil spring and an electronically controlled hydraulic cylinder in series as well as a gas-pressurized shock absorber. Using up to 2,900 psi of pressure, this active body control (ABC) continuously adjusts each wheel's suspension to counteract vibration, pitch, dive, squat and roll. ABC also provides automatic four-wheel level control, driver-selectable ride height and automatic lowering at high speeds. A driver-selectable sport mode for ABC virtually eliminates body roll for even flatter cornering and sharper handling.

More than once in the S65, I fumbled the hunt for the stalk on the left that operates the turn signals, wipers, high beam and cornering lamps, catching instead the shorter stalk above it that controls the Distronic cruise control. Once you've driven with Distronic and sat back, relaxed but vigilant, to let the Benz automatically maintain a selected distance from the car in front regardless of its speed wanderings, regular dumb cruise control seems archaic. Pull out to pass and, sensing the open road again, the Benz resumes the cruise speed it was maintaining before it encountered the slow poke. Always thinking, this car.

Even the backup camera is smart. Laid over the camera picture in the dash is a blue, box-like guidance device that changes shape to function as a projection of where the rear of the car will end up, given current motion and steering-wheel angle. It acts like the velocity vector in a head-up display, and anyone can thus insert the Benz into a space with a precision befitting this shining example of the German motor car craft.

Mercedes and Aviation

On the rare occasions when it could be coaxed out of its coma and actually ran, my 1971 V12 E Type Jag had a sweet spot in the exhaust note at 2300 rpm. The sound was intoxicating. While contemplating the aviation roots of the Mercedes-Benz S65 AMG, I concluded there's one switch missing from the car. It would be labeled UNMUTE V12. The hallmark V12 sound of ripping canvas would be unseemly in a Roller, but in this Mercedes it would be the baring of its soul. There is V12 music there, but it's more audible to onlookers than to occupants.

On a chilly morning, I fired up the S65 cold and got out to sample the acoustics flowing from the four tailpipes. At its enriched idle, the noise was magnificent-precise, insistent and unwavering in timbre, a symphony of mechanical health that seemed to span the octaves.

These Germans ought to know how to build strong, precision engines. The pedigree goes back to World War I fighters and bombers and (photo) the Daimler-Benz DB601 inverted V12 in the Messerschmitt Bf109 of World War II. The Rolls-Royce and Mercedes cars of 2007 seem somehow to have preserved the acoustic characteristics that differentiate the Merlin and the DB601. A richly upholstered, mechanically hushed Phantom car today evokes the grace of a Spitfire and the song of a Rolls-Royce Merlin, which has a mellowness to it that is musical. The Messerschmitt's DB601 sounds altogether more mechanical, more menacing, closer in character to the taut, muscular S65. (Visit www.aircraftrecords.com for superb modern digital recordings of these and many other old aircraft.)

Regardless of the tailpipe decibels that evoke aviation's yesteryears, the S65 packs enough aerospace gadgetry into one vehicle to make any pilot feel at home.

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