For 2007, the V8-powered CLKs have new engines. The CLK550 gets the latest-generation Mercedes V8, with variable valve timing and 27 percent more power than the engine in the 2006 CLK500, yet the same EPA mileage ratings as before. The new CLK63 AMG has a race-inspired V8 built start-to-finish by one technician at the company's AMG high-performance subsidiary.

The new engines mean a slight change in model nomenclature, but the CLK lineup really has not changed. There's still a coupe and convertible, with either a V6 or V8 engine. The super-fast AMG model is available only as a convertible.

The CLK has rear-wheel drive in a class increasingly populated by front-wheel-drive and all-wheel-drive cars, and it has a sporting flair some mid-size luxury cars lack. In general, the CLK is one of the sportiest cars in the Mercedes lineup. Most buyers will be quite happy with the CLK350 and its 268-horsepower V6. With its seven-speed automatic, the CLK350 delivers a fine balance of spirited acceleration, quiet cruising and decent fuel mileage.

Drivers who demand more performance can choose the CLK550. Its new V8 generates 382 hp and an even more impressive 391 pound-feet of torque. (Torque is that force that launches the car from intersections and propels it up hills.) Measured by acceleration and engine response, the CLK550 meets just about any standard of high performance. The CLK550 transmits a feeling of being more stuck to the road than the CLK350 does, with sharper handling and better high-speed stability.

The limited-production CLK63 AMG goes a couple of magnitudes better. It will out-accelerate, out-brake and out-corner all but a handful of four-place cars anywhere. Yet around town it's incredibly docile and belies its 475-hp AMG engine.

On the open road, the CLK, no matter the model, is satisfying, responsive and exceptionally stable at high speeds. It inspires confidence on twisty roads and bears up well in a spirited drive. It's also easy to live with. Its ride is firm, but not intrusive. Its relatively small size makes it easy to park and maneuver in crowded city centers, but its back seat is roomy enough for two adults.

In a word, the CLK is balanced. Its stylish design and elegant interior make it a pleasant place to spend time, and it delivers Mercedes cachet that works in almost any circumstance.