The Bentley Continental GTC Speed is the most powerful car Bentley currently offers. What ' s it like to drive? Bentley makes much of the fact that the Bentley Continental GTC Speed is the fastest open four-sjedala in the world. Its also the most powerful Bentley currently offered, thanks to the McLaren F1-teasing 616bhp boasted by its twin-turbocharged 6. 0-litre engine. What its less keen to publicise is that, thanks to a kerb weight just five kilos short of 2. 5 tonnes, its power-to-weight ratio is inferior to that of a Porsche Cayman R. Consequently, the GTC is everything you dont want in an expensive, fast and sporting car. Which is to say it is both open and heavy.