AUDI has introduced a comprehensively revamped A6 range this week with improved engines, dynamics, comfort, functionality and safety, although a keen eye for detail is required to spot the visual titivations brought upon the five-year-old design.

The A6 Avant wagon is no more in Australia for now, but an updated Allroad quattro arrives, as does a sedan sibling to the RS6 Avant released late last year. This is Audi’s riposte to the Mercedes-Benz E63 AMG and BMW M5.

Finally, the old 4.2-litre V8 and S6 performance sedan also vanish, replaced by an ‘in between’ supercharged V6 model known as the 3.0 TFSI, while a pair of sub-7.0-litre per 100km ‘green’ models designed to dodge the latest luxury car tax will materialise from May, with a 2.0 TDI four-cylinder turbo-diesel opening the A6 range from $74,500.

Initially, then, the $78,500 2.0 TFSI will be the base A6, although it rises by $1504, reflecting range-wide price increases over corresponding outgoing versions. On the other hand, all models gain more features to help offset this.

Trainspotters will tell new A6 from old by the revised grille, rectangular front fog lights, R8-style daytime running lights incorporated into the new headlights, LED turn indicators on the side mirrors, aluminium lower-door sill strip, a reshaped rear bumper boasting a wider diffuser, twin-branch LED tail-lights and fresh wheel designs on often-larger diameter alloys.

Audi_A6_Rear2_Stack1.jpgUnderneath, Audi has attempted to answer criticism over the old car’s ride and (speed-dependent Servotronic powered rack-and-pinion-equipped) steering feel with new shock absorbers and different spring rates, while the quattro all-wheel-drive (AWD) models switch to a more-sports orientated 40:60 front/rear torque split in normal operating conditions, with an ability to send up to 85 per cent of drive to the rear wheels.

Interior changes include the use of more aluminium switches, new colour and trim choices, and a redesigned rear seat that promises greater comfort as well as improved safety. Aiding the latter are revamped head restraints with an anti-whiplash function built-in.

Audi is also offering more standard equipment in all A6 models, led by a redesigned MMI Multi Media Interface that now includes satellite navigation. Called MMI Navigation Plus, it is now more intuitive and faster in operation, thanks to a new joystick-style controller knob. It also features a high-resolution seven-inch screen and a 40GB capacity hard drive, among other items.

New technology options have also filtered up from the latest-generation B8-series A4 released last year, namely the Side Assist lane-change warning system that detects a car in the driver’s blind spot, Lane Assist warning that alerts a wavering driver to stay on the straight and narrow, radar-assisted adaptive cruise control that keeps a steady distance to the vehicle ahead, and a high-resolution rear-view camera to aid reversing vision.

Audi is also bundling popular options together at a lower price collectively than when chosen individually for the Comfort Package (an amalgam of the previous A6’s Comfort and Technik Packages), while the kitted-out S Line sports pack continues.

However, it is likely to be the engine range overhaul that attracts the most attention for the new A6.

Keen to build on the superseded model’s high diesel take-up of almost 50 per cent, Audi has improved the performance, economy and emissions rating of the volume-selling 3.0-litre V6 TDI quattro, due to a 5kW and 50Nm jump in power and torque respectively (to 176kW between 4000 and 4400rpm and 500Nm between 1500 and 3000rpm).

This results in a 0-100km/h dash-time of 6.8 seconds, a top speed of 250km/h, an average fuel consumption drop of 1.4L/100km to 7.1L/100km and a carbon dioxide emissions rating of 189gm/km. Fitted with a diesel particulate filter, it is also classified as an EU5 emissions engine.

Priced from $108,500 (up $2587), the A6 3.0 V6 TDI quattro is still offered with a six-speed Tiptronic automatic gearbox and AWD.

Further, the aforementioned $74,500 2.0 TDI four-cylinder and all-new $84,500 2.7-litre V6 TDI common-rail units introduce a lower-priced entry point for diesel customers.

Eschewing AWD, both have Audi’s Multitronic CVT continuously variable transmission which sends drive to the front wheels only (FWD).

The LCT tax-exempt 2.0 TDI delivers 125kW at 4200rpm and 350Nm between 1750-2500rpm, 0-100km/h in 8.9 seconds, a 218km/h top speed, 5.8L/100km and a CO2 figure of 153gm/km, while the LCT tax-reduced 2.7 V6 TDI tops these with 140kW between 3500-4400rpm, 400Nm between 1400-3500rpm, 0-100km/h in 7.9 seconds, a top speed of a massive 227km/h and 169gm/km.

Yet Audi has big ambitions for its revamped A6 petrol engine range too – in $78,500 2.0 TFSI four-cylinder Multitronic FWD, $92,000 2.8 FSI V6 quattro AWD, and $112,500 3.0 TFSI V6 quattro AWD guises.

This means that the old 188kW/330Nm 3.2-litre FSI V6 quattro, 246kW/420Nm 4.2-litre V8 quattro and 320kW/520Nm 5.2-litre V10 S6 quattro are consigned to history.

The former two are replaced by the all-new 3.0-litre supercharged direct-injection V6 TFSI powerplant. The supercharger is a Roots blower type. Note that the ‘T’ in TFSI now denotes ‘forced induction’ in Audi-speak, rather than ‘turbo’ as it did before.

Pumping out 213kW between 4850-6800rpm and 420Nm from 2500-4850rpm, this 2995cc unit hits 100km/h in 5.9s on its way to a speed-limited 250km/h, 9.5L/100km, and is electronically speed-governed to about 250km/h.

Audi is also making lots of noise about how the 3.0 TFSI’s 210g/km CO2 rating is up to 55gm/km better than either of its predecessors’ efforts.

Buyers can save some $19,500 for the 2.8-litre FSI V6 petrol engine – an Euro V emissions-achieving unit that produces 162kW between 5750-6800rpm and 280Nm between 3000-5000rpm. It accelerates the A6 to 100km/h in 7.7 seconds, can hit 240km/h, returns 9.0L/100km and scores a 215gm/km rating.

With the new base diesel in place, it will be interesting to see if the 2.0 TFSI can maintain its position as the second most popular A6 variant during 2009.

Its credentials are: 125kW from 4300-6000rpm 280Nm between 1800-4200rpm 0-100km/h in 8.5 seconds top speed of 224kmh average L/100km 7.7 and CO2 emissions of 181gm/km.

Meanwhile, the Allroad gains the new 40:60 quattro AWD upgrade and revised 176kW/500Nm 3.0 TDI V6, to boast a 0.4-second 0-100km/h improvement (down to 7.4 seconds), a fuel consumption drop of 15 per cent to 7.5L/100km and a 199gm/km CO2 result – at an increased cost of just $21.

However, the MMI Navigation Plus costs extra in the Allroad – but Bluetooth is now included as standard. Buyers will be able to pick new from old by the LED tail-lights, indicators in the side mirrors, and fresh wheel design.

The Allroad is expected to perform better now that the A6 Avant is gone, Audi believes, as the former’s cargo-carrying capabilities are on a par with the latter’s.

Finally, the sedan version of the performance-flagship RS6 Avant rounds out the 2009 A6 changes.

Choosing the $263,500 sedan saves $7400 (while the RS6 Avant’s price has risen by almost $1000), but it still uses the same 5.2-litre FSI twin-turbo V10 petrol engine with dry-sump lubrication delivering 426kW of power from 6250-6700rpm and 650Nm of torque from 1500-6250rpm.

At 4.6 seconds to 100km/h, the RS6 sedan is 0.1 seconds faster while maintaining a governed 250km/h maximum speed. It also uses 0.1L/100km less fuel (at 13.9L/100km) and is marginally less polluting, at 331gm/km of CO2 (versus the RS6 Avant’s 333gm/km).

Both versions include a modified six-speed Tiptronic automatic gearbox with faster responses, a specially tuned ESP stability control system with higher threshold activation software, 40:60 rear-weighted quattro AWD with the ability to send up to 65 per cent of torque to the front wheels and up to 85 per cent to the rears, depending on conditions.

Other inclusions are Dynamic Ride Control adjustable dampers with sports suspension, 20-inch alloy wheels shod with 275/35 tyres, six-piston fixed aluminium callipers working on 390mm front disc brakes and a single-piston floating rear calliper on 365mm rear discs, an RS6-specific body kit with special Xenon-plus adaptive headlights, MMI Navigation Plus with TV, sunroof, and upgraded climate control, among a host of other standard-fit items.

Buoyed by the facelift and lower entry-level models, Audi is quietly confident it can increase overall A6 sales from last year’s 580 total (against 1383 BMW 5 Series, 1170 Mercedes E-class and 419 Lexus GS).

Last year’s A6 result represented a 172-unit slide from 2007, in a segment that also saw the aforementioned competitors lose customers year-on-year.

Diesel sales should account for at least half of all A6 volume, with the base 2.0 TDI gunning for the BMW 520d – which is the Bavarian company’s bestseller in the series.

In Europe, the A6 outsold all its rivals last year.