The Mercedes-Benz CLK-Class two-door coupes and cabriolets receive only minor updates for 2009. The automaker adds heated front seats as standard equipment for all CLK-Class vehicles, as well as a standard six-disc CD changer mounted in the glovebox, which conceals it from view yet ensures easy access by drivers and passengers. Among other features, the CD changer plays MP3-coded CDs. In addition, drivers can control the CD changer using buttons mounted on the multifunction steering wheel.

Mercedes offers the CLK-Class in four trims for 2009, including the CLK350 Coupe, the CLK350 Cabriolet, CLK550 Coupe, and CLK550 Cabriolet. All are rear-wheel-drive vehicles, and seat four passengers. In addition, all CLK-Class vehicles retain their broad stance and pillarless cabin design, which results in an airy, uninterrupted side profile with the windows opened or closed. The current design dates back to 2003 (2002 for the coupes), so the CLK-Class coupes and cabriolets feel a bit dated. However, Mercedes will give the CLK-Class a design refresh in 2010, making 2009 the final year of the current design.

A 268-hp, 3.5-liter V6 powers the CLK350 Coupe and CLK350 Cabriolet. For both trims, the V6 links to a seven-speed automatic transmission, making the CLK-Class cars the only ones in their class with a seven-speed automatic, according to Mercedes. A 382-hp, 5.5-liter V8 engine drives the CLK550 Coupe and CLK550 Cabriolet. Both also feature the seven-speed automatic transmission, as well as 18-inch AMG-designed five-twin-spoke wheels (as opposed to 17-inch wheels for the CLK350 trims).

Across the line, standard features include 10-way power-adjustable front seats, a driver's multicontour seat with adjustable side bolsters, leather upholstery throughout, dual-zone automatic climate control, a heated windshield washer system, and the Keyless-Go system, which enables drivers to lock and unlock the vehicle and start and stop the engine with using a key. In addition, all trims except the CLK350 Coupe come equipped with a sport suspension, which includes a lower ride height and firmer coil springs and shock absorbers, resulting in more precise handling. The system is available as an option on the CLK350 Coupe.