CHANDLER, Ariz. -- On a long straightaway of the East Test Track at Firebird International Raceway, a circuitous race track in the Arizona desert near Phoenix, the only speed limit in force for our test laps in a high-performance sports sedan from Mercedes-Benz comes from an electronic governor on the powerful AMG engine, and a rapidly approaching hairpin curve at Turn 4.
Our car -- the elite C63 AMG -- stocks a hand-built powerhouse of an engine worth more than 450 horses so it's capable of running quite comfortably at twice the legal speed limit on USA freeways.
However, it also packs a dazzling collection of computer-based electronic controls plus handling hardware honed from competition in international touring car races, including humongous disc brake rotors which are internally ventilated and perforated, then activated by electro-hydraulic means with six-piston calipers up front and four-piston fixed calipers in back.
We cite the brake components specifically because in our approach at triple-digit speed to the hairpin Turn 4 those brakes must arrest the inertial mass of nearly two tons of slick automotive metal in the scant length of a football field in order for us to steer this supercar through the double-apex line of a too-tight corner manageable only at speeds below 40 mph.
Then, in swift sequence through the kink with some wide-base tires squawking, this car shows us how agile and athletic it can act.
Whip, zip, rip -- it charges around the corners.
Safely tracking out of the curve, we punch the throttle again as shoulders pin against the bolstered sport bucket and those growling deep engine notes spew from two twin-tip exhaust pipes.
This is too good: Only the first of many laps taken around the track at Firebird convinces us that this car easily tops the chart of compact-class performance sedans.
The C63 AMG amounts to a remarkable V8-powered supercar cast in limited numbers and designed for those who lust after awesome automotive performance in a supreme compact-class machine cloaked in the sedate disguise of a family sedan.
Mercedes makes supercars like the C63 AMG a rarity.
In 1968, the 300SEL 6.3 full-size luxury sedan contained a 6.3-liter V8 to move it from zero to 60 in under seven seconds, while ten years later the 450SEL 6.9 used a larger version of this V8 to haul the big car to 60 mph in less than eight seconds, and in 1992, the E500 sedan got the 5.0-liter V8 from a roadster SL500, earning sub-six-second zero-to-60 times.
Then in 1998 a compact-size C Class sedan, following special powertrain and bodyworks modifications by specialty tuner AMG, forged the high-performance C43. It was followed by the first E55 AMG cast off the previous generational version of the E Class sedan.
Today, the Mercedes line includes an AMG performance-tuned special edition in virtually every class for an exclusive sub-line of high-performance vehicles.
The initials of AMG represent the last names of founding partners Hans-Werner Aufrecht and Erhard Melcher, plus the town of Aufrecht's birth in Grossaspach, Germany.
A new design for the Mercedes compact-size C Class sedans rolled out as 2008 issues with three V6-powered models -- C300 Sport, C300 Luxury and C350 Sport. These are rear-wheel-drive (RWD) vehicles, although optional 4Matic all-wheel-drive (AWD) equipment is offered for C300 models.
Then, with the C Class structure serving as a blank canvass for the latest collaboration between Mercedes and AMG, the performance gurus at AMG's facility in Affalterbach, Germany, build the new C63 AMG performance edition using a balanced and tuned V8 with unique exterior body parts, an AMG-designed low-restriction exhaust system and performance-geared brake and suspension hardware.
The body of C63 AMG varies from other C Class cars due to the unique design for a front hood with bulging power domes, plus broader front fenders which house the wide-tread tires and special air-grabbing fascia up front with pencil-beam foglamps defined by chrome rims.
A visit to the AMG engine plant in Affalterbach reveals that one skilled engine technician assembles the C63 engine entirely by hand.
The V8, displacing 6.2 liters, features a block composed of high-strength silicon-aluminum alloy with four valves per cylinder, variable valve timing and a magnesium variable intake manifold.
It develops 451 hp at 6800 rpm and peaks the torque at 443 lb-ft at 5000 rpm -- with 370 lb-ft of torque available at only 2000 rpm.
Transmission is the Mercedes SpeedShift Plus seven-speed manual automatic transmission with double-clutch rev-matching during downshifts and paddle shifters mounted on the AMG steering wheel.
How fast will the C63 AMG go?
It's so quick you can move into the realm of illicit speed faster than you might say, "Hello, Officer."
AMG lists the official 0-to-60 mph acceleration time for a C63 at 4.3 seconds.
An electronic governor on the AMG V8 engine restricts the top speed for C63 to 155 mph, although an optional performance package with locking rear differential raises that top-speed figure to 186 mph.
There are multiple devices aboard the C63 AMG to stabilize all forward movement and tire traction.
Sensors in the suspension system determine vehicular payload, speed and road conditions, and they can adjust dampers on shock absorbers to smooth out or firm up the ride quality. Still other devices measure wheel speed and lateral acceleration and can brake an individual wheel to correct potential skidding or spinning of the car.
Also on tap is the alphabet soup of computerized vehicle controls -- anti-lock brake system (ABS) with brake assist plus (BAP) and electronic stability control (ESP).
And Mercedes provides roll-over sensors, curtain-style air bags for outboard seats on both rows in the cabin, plus smart two-stage frontal air bags, side air bags for front seats, even an air bag shielding the driver's knees.
The cockpit contains power everything with a glass sunroof, dual zone climate controls, split-folding back seats and two AMG sport bucket front seats in leather with integrated head restraints and adjustments for the side bolsters and lumbar support.
MSRP for the 2009 C63 AMG comes to $57,175, but there are optional packages such as bi-xenon headlamps ($1,080), multimedia navigation ($2,950) and AMG performance ($3,900).