The Mercedes CL-Class shows, like the previous two entries, that a big twelve-cylinder engine usually leads to a heavy car. In the case of the CL65 AMG, it’s a twin-turbocharged 6.0-liter V-12 that churns out 621 hp and 738 lb-ft. A five-speed automatic transmission directs that power to a pair of 20-inch wheels and tires at the rear axle. Mercedes says 60 mph arrives in just 4.3 seconds, and top speed is limited to 186 mph. This is a seriously fast coupe despite its prodigious weight. There are, of course, three other versions of the CL-Class that are somewhat lighter, but still none are featherweights. The CL550 measures just 4619 pounds, equipped with its 429-hp, twin-turbo 4.7-liter V-8 engine. The CL600 has a 510-hp 5.5-liter twin-turbo V-8 and weighs 4894 pounds. And finally, the CL63 AMG comes in at 4894 pounds and packs a 5.5-liter twin-turbo V-8 good for 536 hp.