WHEN Audi set a benchmark as high as the fifth-generation A4 last year, it was always going to be a hard act to follow with an even sharper S4 performance version, but the initial signs are good on paper.

With a 3.0-litre TFSI V6 that has adopted a single turbo in place of the previous supercharged unit, the new S4 has gained 15kW and 60Nm, and thanks to a weight reduction of 75kg, zero to 100km/h acceleration has dropped to 4.7 seconds or 4.9 for the slightly heavier Avant wagon.

Its new look may not be a massive departure from the fourth-generation A4 and S4 but it certainly sharpens the overall effect and Audi says an extra $12,000 worth of equipment will sweeten the deal even further.

But it’s not until you meet the all-new S4 in person that you realise just how comprehensive and impressive the improvements have been across the board.

Clean lines, beautiful proportions and subtle but effective details such as the optional Matrix LED headlights combine for a seriously good-looking car that resists conspicuous styling cheap tricks in favour of mature, subtle design.

Spend $3000 on top of the $99,900 sedan and Audi will put an S4 Avant on your driveway which is our pick of the range. There are few things cooler than a sexy wagon with a firecracker under the bonnet.

Hop in and the interior doesn’t just equal the squeaky clean exterior aesthetics, but even betters them with typical Audi build quality, aesthetic restraint and superb ergonomics from carpet to roofliner.

Our car had been decked out with an optional S performance pack for $5900 which replaces standard matte aluminium trims with high-quality carbon-fibre finishers, applies synthetic leather to more areas of the dashboard and installs S sport front seats in Nappa leather.

The upgraded seats look fantastic with contrasting diamond stitching, massage functions and an elegant design, but the incorporated headrest doesn’t adjust which may be a problem for taller drivers.

One of our test vehicles was dressed up in a conservative Manhattan Grey metallic paint but was wearing the automotive equivalent of sexy undies in the form of a gorgeous red leather interior – a fabulous combination.

Other S4 unique features include the excellent D-shaped sports steering wheel which was ergonomically excellent but could have lost a little girth for perfect comfort, black roofliner and a scattering of S badges including in the virtual cockpit digital instrument cluster – another feature from the standard A4 that we rate very highly.

We nestled into the sports seats and got chatting to our travel companion for a stretch of freeway touring and were surprised at how quiet and composed the cabin is at cruising speeds, despite firm suspension and 19-inch alloys, which had been upgraded to the prettier no-cost-option matte Titanium versions.

Ride comfort is top-notch thanks in part to the standard adaptive dampers which allow a softer setting when the drive select mode is switched to comfort, auto or efficiency but we found the dynamic setting to be firmer and more enjoyable without compromising on comfort.

The S4 ride and touring manners are so accomplished that you might forget it has an S badge on the boot and 260kW on tap for all four tyres, but turn off the highway and on to your favourite twisty section and Audi’s latest sports sedan comes alive.

At its core, the new TFSI turbo V6 is a sensation, bringing 500Nm of torque from just 1370 rpm, minimal turbo lag and smooth power delivery, but at higher revs the vocal exhaust note is almost as shouty as the Volkswagen Golf R32 accompanied by strong acceleration all the way to the red line.

We particularly liked flicking the eight-speed automatic transmission in to manual mode and holding the 3.0-litre engine in higher gears to enjoy the turbo whistle and delightful warble from about 2500rpm under load.

The S4 doesn’t initially feel as fast as its figures suggest thanks to slick gearshifts and linear power delivery, but speed builds almost like an electric car. The S4 is very capable.

Rather than the company’s dual-clutch auto, the S4 has adopted a tiptronic torque-converter automatic, which works beautifully when paired with the strong engine. In auto mode, gearshifts are intuitive with skip-shifts for more responsive acceleration and fast cog-swaps when asked for a different gear when using the steering wheel paddles.

Audi still hasn’t responded to countless driving enthusiasts around the world and flipped the gear selector switch around to allow down-shifts with a push forward of the gear lever and up a ratio with a pull back, so we stuck to the paddles.

Another agreeable option for true petrol-heads would be the manual gearbox that is offered in Europe but packaging and engineering difficulties limit the option for right-hand-drive cars, as is often the case. Yes we know Australians almost exclusively buy autos but Audi would gain performance stature if it acknowledged the handful of aficionados.

But easily the S4’s party piece is the Quattro all-wheel drive system that has defined so many great Audis before it, bringing a tractor-load of traction for all driving conditions.

Turn the S4 into a sweeping bend and it responds with decent sure-footedness that is comparable to its rivals which prompted us to keep trying harder.

Delightfully, with each sharper or more aggressive corner, the Audi simply found a line and stuck to it with the stubbornness of a Taurean draught horse.

None of its European competitors can offer the same talon-like grip.

Our car was fitted with the standard torque vectoring system and an optional $2950 Quattro Sport differential which combined for the most impressive road-holding. We simply could not provoke the S4 to break from its staunch line and trying any harder would have been downright irresponsible.

The limitless grip was complemented by a sophisticated steering system that is one of the most impressive we have experienced from the four rings to date.

While a touch more feedback would be appreciated, the general feel, weight and precision are of a very high standard.

Front end feel is also surprisingly sharp with a rapid turn in which suggests a very light powerplant that is set far back in the chassis – how very different from the early Quattros that had heavy iron blocks far out ahead of the front axle.

The all-new Audi S4 is such an immensely impressive combination of comfort, performance and sharp design at a sharp price that it is hard to fault, but it may have generated a new challenge for itself.

The car-maker is yet to officially confirm a replacement for the previous-generation RS4 hyper wagon, but if it does, the new RS4 is going to have to deliver something monumental to distance itself from the brilliant S4.