Bentley’s sporty GT Speed coupe has been on sale since August 2007 and back in June last year we saw the introduction of the Flying Spur Speed saloon. However, there’s one more derivative of the Bentley Continental family that is yet to receive the Speed treatment and that is the stylish GTC convertible, which is set to make its debut next month at the Detroit Auto Show.

The new model is Bentley’s most powerful convertible ever and inspired by Bentley’s legendary ‘Speed Models’ from the 1920s. Like the previous Flying Spur and GT models, the GTC Speed will feature an uprated version of the standard car’s twin-turbocharged 6.0L W12 engine. Specific changes to the engine include a new crankcase design, a lighter camshaft chain and a faster cam sensor, as well as increased boost pressure from the turbos.

The mega powerplant is officially rated at 600hp (448kW) and 553ft-lb (750Nm) of torque in the Speed models, and will push the car to a top speed of 200mph with the roof up. When lowered, top speed is reduced to a still impressive 195mph. The 0-60 mph sprint is despatched in 4.5 seconds and 0-100 mph in 10.6 seconds.

The six-speed transmission can be left in two fully automatic modes (Drive and Sport) or used as a pseudo manual where the driver can change gears sequentially, via either the gearlever or paddles mounted behind the steering wheel.

Other Speed attributes include 20in wheels, a stiffer suspension and a unique front bumper. The radiator grille is more upright with a more pronounced square edge, accentuating the Bentley profile, and bolder lower air intake. Inside, the car gets the usual plush Bentley appointments such as Nappa leather trim, seat piping, a 1,100W Naim audio system, and plenty of wood and chrome.

For the standard GTC, new low-friction dampers provide improved ride comfort. In addition, two significant new options may be specified on both the GTC and GTC Speed: lightweight, fade-resistant, carbon-ceramic brakes - the largest production passenger car brakes in the world - and a sophisticated follow-to-stop Adaptive Cruise Control system with long-range radar sensor that monitors traffic ahead and manages throttle and brakes to maintain a driver-selected time gap. Output for the GTC is rated at 552hp (411kW) and 479lb-ft (650Nm) of torque.