At the end of last year Audi revealed the S8 at the Tokyo Motor Show, with a fantastic 5.2-litre V10 powerplant under the aluminium bonnet. At this week's Detroit Show Audi unveiled its younger brother, the S6, with the same outrageous powerplant squeezed into the A6's engine bay.

The Audi S6 will be available in saloon and Avant (estate) guises, with sales starting before the summer. Though it is tempting to compare the new Audi S6 to BMW's M5, they are quite different beasts. The Audi S6 has permanent four-wheel drive with a 40/60 front/rear split of torque for a more sporting drive. In terms of performance, the S6 is no slouch, with 0-62mph in just 5.2 seconds (the BMW manages a scarcely believable 4.7 seconds) and a top speed limited to 155mph. The V10 engine is based on the unit used in the Lamborghini Gallardo, though modified. In the Audi S6 its output is 'only' 420bhp though there is a healthy 384lb.ft of torque available between 2500 and 5500rpm.

Unlike its Lamborghini cousin, the Audi S6 does not shout about its performance. Actually, we think it is a little too restrained. The new design of 19-inch alloy sit behind subtly flared wheel arches, and the grille is a little different to the rest of the A6 range, with new LED daylight driving lights. There are the obligatory four exhaust pipes and the Avant has a slightly larger rear spoiler. Inside, the 2006 Audi S6 is beautifully built and trimmed in Alcantara and leather. The only gearbox available at launch is a six-speed automatic.

Watch out for our review on the Audi Road Tests page.

Shane O' Donoghue - 26 Jan 2006