Among the CTS Coupe Concept’s signature design cues are a number of elements that suggest the look of a carefully cut diamond – particularly at the rear. These elements are seen in everything from the chrome header above the rear license plate holder to the indents that comprise the basic form of the rear fascia.

Although based on the sedan, the CTS Coupe shares only the instrument panel, console, headlamps, front fenders and grille with the production model. Unique elements include:

-Classic hardtop styling, with no B-pillar -CTS production windshield laid at a faster angle to create a sleeker profile -Chrome, split seven-spoke wheel design; 20-inch front wheels and 21-inch rear wheels -Sculpted lower front fascia with unique brake-cooling vents -Slim-profile outside mirrors -XLR-type hidden door handles with proximity remote opening -Unique front fender vents -Diamond-cut rear fascia with mesh lower grilles and center-outlet exhaust -Taillamps with a subtle fin profile and are highlighted with LED lighting technology with light pipes -Rear spoiler integrated into the center high-mounted stop lamp -Sculpted roof-mounted antenna for OnStar, XM Satellite Radio, etc.

The surfaces of CTS Coupe Concept are complex, inviting careful inspection. The rear fenders, for example, were sculpted by hand in the design studio until they provided a perfect, muscular form that wrapped tightly over the wheels. At the top, the rear fenders are beveled – owing to the diamond-cut theme – and become part of a horizontal plane that runs from the leading edge of the taillamps and merges into the roof.

Personal passenger environment

A classic 2+2 interior environment enhances the CTS Coupe’s personal feel. It shares the hand cut-and-sewn instrument panel and center console with the CTS, but features unique front and rear seats, a continuous console running between the front and rear seats, and custom door panels.

“The CTS Coupe is a personal car – something a customer would choose to reward him or herself – and the passenger environment reflects that,” said Eric Clough, interior design director. “The interior uses the already excellent CTS design and takes it to a new, bolder level.”

Custom-trimmed sport seats from Recaro are located in all four positions. They support the grand-touring nature of the car and are covered in rich, black and suede-like microfiber material, with yellow ochre-colored inserts. The yellow ochre color provides dramatic contrast with the black surrounding trim, but is a subdued hue consistent with the interior’s overall feeling of refinement. Yellow ochre stitching also is used throughout, including the seats, instrument panel, shifter knob and more.

Black microfiber fabric covers the front armrest, as well as an armrest located between the rear seats. The armrests are part of a continuous console that stretches from the instrument panel to rear seats. Carbon-fiber trim accents the console. The interior also features ambient lighting throughout, creating a distinctive environment at night.

Like the sedan, the CTS Coupe Concept’s interior is home to a host of technologies, including a premium Bose audio system, 40-gigabyte hard drive and XM Satellite Radio. OnStar with Turn-by-Turn Navigation enhances the vehicle’s onboard navigation system, which – like the CTS – features a screen that rises out of the center of the instrument panel.

Performance-bred powertrain and suspension systems

As is the case with its design, the CTS Coupe extends the acclaimed capabilities of the sedan in terms of performance technology. This includes the capability to support a broad engine range of gasoline and diesel engines.

The CTS Coupe, of course, ascertains the sedan’s 3.6L V-6 engines, including the 304-horsepower (227 kW) Direct Injection power plant. The Coupe Concept also is designed for a new 2.9L turbo-diesel being developed for international markets. This new engine, tailored for use in the CTS, will deliver an estimated 250 horsepower (184 kW) and 406 lb.-ft. of torque (550 Nm).

A six-speed manual transmission backs the engine, sending torque to an independently sprung rear axle. The CTS Coupe’s sport-tuned suspension gives it a slightly lower ride height than a production CTS – a look enhanced by the car’s rakish shape and large, 20-inch front and 21-inch rear wheels.

Behind the chrome, split-spoke, aluminum alloy wheels is a set of high-performance brakes, featuring cross-drilled rotors. Six-piston calipers clamp down on the front rotors, while four-piston calipers grab the rear rotors. All of the rotors have a distinctive, yellow-painted finish.