AUDI Australia has released the most overtly sports-focused A4 sedan in its history, as well as the most expensive.

Priced from $164,500 - a $33,300 premium over the S4 Tiptronic automatic and $26,600 above the price BMW commands for its E46 M3 coupe - the RS4 quattro is a development of the B6 S4 sedan released in Australia last November.

Having said that, the manual-only RS4 is $500 less expensive than the 50 old-shape (B4) A4-based RS4 Avants sold in Australia from late November 2000 to mid-2001.

Sitting at the top of the A4 range, the latest RS4 features a 4.2-litre direct fuel injection V8 engine delivering 309kW of power at 7800rpm and is capable of spinning right up to 8250rpm.

Its maximum torque of 430Nm comes in at 5500rpm with 90 per cent of the engine’s torque available from 2250rpm to 7600rpm. This compares to the 280kW and 440Nm developed by the old RS4 Avant’s twin-turbocharged 2.7-litre V6.

Like its predecessor, power is relayed to all four wheels via a six-speed manual gearbox.

Using 98 RON premium unleaded fuel, such performance enables the 1650kg RS4 sedan to rocket to 100km/h in 4.8 seconds and 200km/h in 16.6 seconds.

Swept along by a 0.31Cd aerodynamic drag-coefficient rating, the RS4’s maximum velocity is vetoed at 250km/h via an electronically controlled cut-out device.

Overseas fuel consumption figures released by Audi indicate that the RS4 averages around 13.7L/100km, while its carbon dioxide output from its Euro IV-compliant V8 is 322-324 grams per kilometre.

The RS4 quattro is also the first Audi in Australia to utilise the company’s new sports-focused all-wheel drive system.

Its asymmetric/dynamic torque distribution, in concert with a self-locking Torsen centre differential, delivers 40 per cent of drive to the front axle and 60 per cent to the back wheels, for rear-wheel drive-like dynamics, control and feel.

The quattro gear complements Audi’s DRC (Dynamic Ride Control) suspension system, which reduces rolling and pitching, while the steering has been tuned for more direct response.

The S4’s brakes have also been seen to, with an enlarged 18-inch system for improved stopping performance, featuring cross-drilled, inner-vented discs that are 365mm in diameter at the front and 324mm at the rear.

These are aided by special flow-optimised ventilation courtesy of a Naca jet spray apparatus built on the RS4’s underfloor, for better brake cooling under many varied conditions.

Visually, the RS4 sits 30mm closer to the bitumen compared to the standard A4 sedan, and features a slightly wider front and rear track.

Additional air intake scoops in the front section of the single-frame grille, as well as the addition of added flaring in the bumpers, add a more menacing mien to the Audi.

Large twin-exhaust pipes betray the RS4 from behind, while the cabin includes leather upholstery, plenty of aluminium trim, and even some carbon fibre elements.

A push-button ignition procedure brings a further sense of occasion to the RS4, compared to its more humdrum siblings.

The driver can also modify the accelerator mapping by pressing the “sports” button in the steering wheel, providing sharpened and more direct engine response.

Audi will follow the RS4 sedan with the $168,100 RS4 Avant in October, featuring the same level of performance and equipment.

Combined sales are forecast to be 100 for 2006 and 70-80 next year.