Audi is to produce an RS version of the A7 soon after the four-door coupe goes on sale as a 2011 model.

The Audi A7 Sportback is nearing the end of its development. Autocar reports that an official unveil will take place at this year's Paris Motor Show in September. UK sales would probably start in the first quarter of 2011.

Alongside smaller-engined variants like V6 petrols and diesels, the A7 will also get a thunderous RS 7 model. It is said to churn out 433 kW (580 bhp / 588 PS) from its 5.2-litre naturally aspirated V10 engine according to Autocar, although the 5.0-liter TFSI V10 from the RS6 with its 572 bhp (427 kW / 580 PS) might be a better candidate. Running all four wheels would be a 7-speed double clutch gearbox.

A four-door Sportback concept was first unveiled at the 2009 Detroit Motor Show. The production version, spied time and time again, is a primary competitor to the Mercedes-Benz CLS and a secondary rival to the likes of Porsche Panamera and Aston Martin Rapide.

Gallery: Audi A7 Sportback to be unveiled in Paris, RS7 to get 580 bhp