BMW is about to launch the X6, a rival to Porsche's grotesque Cayenne SUV, which will be available with a 408bhp twin-turbo V8.

It boasts a 3.7-liter twin-turbo flat-six delivering 740 horsepower, and can reach 62 miles per hour in 2.8 seconds, with a top speed of 245 mph.

U. S. buyers will first see the S-class as the S550, with a twin-turbo, 4.6-liter, 449-hp V8 under the hood and a seven-speed automatic, in either rear-drive or all-wheel-drive configurations.