Used 2001 Mercedes-Benz CLK-Class Coupe

Like all businesses, the one Hans Werner Aufrecht and Erhard Melcher conceived in the town of Groaspach, Germany, 34 years ago, started with big hopes for success. Taking the initials of the two founders last names and their hometown, they called the company AMG. Those hopes have been exceeded.

And excessive is exactly the word to describe the new Mercedes-Benz CLK55 AMG.

The CLK55 is Mercedes' smallest coupe (seen before as the 3.2-liter V6-powered CLK320 and 4.3-liter V8-equipped CLK430) transmogrified by the insertion of AMG's biggest and most powerful V8. It's a mutant, warped by the presence of the hand-assembled 5.5-liter engine under its hood that throbs out 342 horsepower and enough torque to pull the truth out of the Warren Commission.

Forget everything else about the car; it's the engine that's the star here. And it's a familiar star; the same motor that's in the ML55 AMG sport-ute, the E55 midsize four-door and soon the forthcoming CL55 and S55 full-size coupe and sedan. Except for the displacement (which, at 5439cc, is a stretch for AMG to call a 5.5-liter) the general engine specs are rather ordinary Mercedes-stuff.

As in every other current Mercedes V8, the AMG 5.5's block is aluminum, there's a single cam over every aluminum head operating two intake valves and one exhaust valve per cylinder, and each of those cylinders is fired by two spark plugs. But AMG adds a forged-steel crankshaft with a long 92mm stroke (up from the 5.0-liter version's 84mm), installs hollow, lightweight modular camshafts of longer duration, and shapes every combustion chamber for maximum airflow. An oversize air cleaner allows the ingestion of atmosphere in Superdome-size gulps while a modified intake plenum makes sure that air is distributed efficiently. It's all basic no-replacement-for-displacement hot rodding and it works.

The AMG V8 ignites to a rumbling idle that's less muted in the CLK than in the E55 or ML55, and revs with a snarl that's startling in its ferocity. It's lashed to a five-speed automatic transmission stolen from Mercedes' V12 parts bin that's fortified with a larger housing and had "Touch Shift" added, which is the company's take on the mania for shiftable automatics (it works by bouncing the shifter to the left for downshifts and to the right for upshifts). As far as shiftable automatics go, this one works well. But hardcore drivers will still crave a six-speed manual.

Mercedes claims the CLK55 will bolt to 60 mph in just 4.9 seconds, making it the quickest car they've ever sold in the United States. But it's not speed itself that welds this car to a driver's soul; it's the overwhelming sensation of thrust. AMG's magic tweaks have this engine making heaps of torque from just off idle to a peak 376 foot-pounds at just 3,000 rpm. It's muscle car-like; more akin to a '70 Chevy Chevelle SS 454 LS-6 than this car's most obvious direct competition, the 333-horsepower 2001 BMW M3 which produces its 262 foot-pounds maximum at a screaming 7,900 rpm. This is an engine that doesn't need to rev to perform. But it will rev ravenously until the car hits its 155-mph speed limiter.

The engine is so flexible, so friendly and so forgiving that it would flatter a Conestoga's chassis. But AMG optimizes the CLK55 by tightening the ride motions with stiffer springs, tighter shock valving and thicker anti-sway bars on the double-wishbone front and five-link rear independent rear suspension. Surprisingly, the AMG "Monoblock" wheels and tires remain the same size as those on the CLK430. That means the front 17x7.5-inch wheels are encased in 225/45ZR17 rubber and the rear 17x8.5-inchers in 245/40ZR17. That's plenty of tire and while the steering lacks the instant reflexes and confident communication of a BMW, this is the best Mercedes has yet offered.

On a track, having fun in the CLK55 means turning off the standard ESP stability control and ASR traction control (both of which are unobtrusive and effective on the street). Diving into a corner, the car clamps down with massive 13.2-inch diameter front discs and the driver can drift the tail to overcome the car's inherent understeer with easily managed throttle. It's wonderful.

If there's anything disappointing about the CLK55 it's that there's no way to easily distinguish it from a regular CLK430. There are xenon headlamps and the body bits are slightly different between the two cars, but the wheel design is similar and it'll take a real connoisseur to tell the two apart instantly.

As in every CLK, the AMG version's innards are tastefully appointed and roomier than many larger coupes. The front seats are snug enough for wacky driving antics and broad enough to accommodate even wide-butt journalists. There are maybe too many controls on the steering wheel, and the radio and ventilation controls need deciphering by an archaeologist versed in Germanic culture, but acclimation comes quickly. In an accident the driver and front passenger get front, door, and side curtain airbags and Mercedes' Tele Aid system will summon help by transmitting the car's GPS-determined location to the authorities. The only options are a CD changer, phone, and navigation system, though buyers do get to choose between two Designo color and trim packages. At a $67,400 base price (almost $18,000 pricier than a CLK430), everything should be standard.

Hans and Erhard's business grew so successful in both tuning and racing that Mercedes bought them out in 1999 and now uses AMG as an in-house tuning shop and competition department. With cars like the CLK55 wearing their initials, they've got to be happy about more than the size of their buyout checks.