The first official details of the Audi S4 sports saloon and Avant estate have been released with the performance car boasting 339bhp.

The big news is under the new Audi S4’s bonnet where the old car’s V8 has been replaced by a new supercharged 3-litre V6 with direct fuel injection.

Audi S4 slide show

This smaller engine has 339bhp and 325lb/ft of pulling power allowing it to accelerate from 0-62mph (100km/h) in 5.1 seconds – half a second faster than the previous generation Audi S4, while its top speed is electronically limited to 155mph.

It will be competing in a hard fought arena with key competitors including the BMW 335i, Mercedes C350, Mitsubishi Lancer Evolution X and Volkswagen Passat R36.

The new S4 is also considerably greener than its predecessor - averaging 29.1mpg on the combined cycle (up from 21mpg).

The exterior makeover is subtle and features new alloy wheels, chrome exterior mirror housings and aggressive bumpers.

A six-speed manual gearbox is standard but a seven-speed DSG semi-automatic gearbox will be an optional extra.

Quattro four-wheel-drive sends 60 per cent of the engine’s torque to the rear wheels in normal driving and can shuffle power to each wheel if necessary.

A new ‘Active Sports Differential’ limits understeer by sending more power to the outside wheels during cornering to push it around the bend.

Sports suspension drops the ride height by 20mm and uses aluminium components to keep weight low and improve ride and handling.

The Audi S4 saloon and Avant will make their world debut at the Paris Motor Show in October. Be sure to check back as we bring you all the latest news from the show.

Full details of a brand new Lamborghini will also revealed at the show. It has been speculated it could be anything from an entry-level Audi R8 rival to a performance off-roader.