AUDI Australia has given its volume-selling A4 sedan and wagon line-up a comprehensive midlife update, cutting prices on most variants while adding a range of new and improved engines with more power and better fuel efficiency.

On sale from July 7, the update also sees the introduction of the S4 Avant, a load-lugging wagon version of the 245kW/440Nm supercharged flagship sedan, giving the Ingolstadt company a potential rival for the more powerful and expensive Mercedes-Benz C63 AMG Estate.

Audi will be banking on the model revision to turn around a 16.7 per cent drop in A4 deliveries this year, with sales trailing well behind the segment-leading Mercedes-Benz C-Class and the recently released new-generation BMW 3 Series.

The updated range now comes with seven different engine options – three diesel and four petrol – all of which feature forced induction, idle-stop and direct injection, and which consume on average 15 per cent less fuel.

All front-drive A4 models are offered with a continuously variable transmission (CVT), while quattro all-wheel-drive offerings get a seven-speed S tronic dual-clutch automatic. Only the entry 1.8 and 2.0 TFSI petrol variants are available with a six-speed manual.

Other notable changes include subtle styling changes to the nose and tail, a new and more efficient speed-adjustable electro-mechanical steering system, a revised interior featuring new materials and a sportier steering wheel, and an upgraded optional adaptive cruise control system.

While Audi expects the (now $200 cheaper) 1.8 TFSI entry variant to narrowly remain the top-seller, the company has embarked on an even more aggressive push on the mid-range 2.0 TFSI quattro sedan, which it claims occupies the “sweet spot” in the range.

Prices on this all-wheel-drive variant have been slashed by as much as $8000, now starting at $61,700 plus on-road costs for the manual sedan and climbing to $67,500 for the automatic Avant with new standard features such as MMI satellite-navigation and 18-inch alloy wheels.

Outputs of 155kW and 350Nm are unchanged over the previous 2.0 TFSI, but fuel use has been cut by 0.6L/100km to 6.8L/100km (7.0L/100km for the auto), allowing it to sneak below the luxury car tax threshold.

While pricing on the 150kW/400Nm 3.0 TDI V6 (sedan and wagon) is up $900 over the 2.7 TDI it replaces, power is up 10kW and fuel consumption has been slashed 23 per cent to just 4.9L/100km. Audi Australia has further softened the blow by stuffing a claimed $8000 of extra features into the revised model, including Xenon headlights, 18-inch alloy wheels and keyless start.

The same potent six-cylinder oil-burner has also been massaged to produce 180kW and 500Nm of torque when matched to a rear-biased all-wheel-drive system in the 3.0 TDI quattro (from $88,000), which allows the car to sprint from zero to 100km/h in 5.9 seconds while consuming just 5.7L/100km.

The entry 2.0 TDI is the only other variant to cop a price increase – up by $1700 in both sedan and wagon forms – but this is countered by the updated 2.0-litre engine that produces an extra 25kW/60Nm while returning fuel consumption of 4.8L/100km – 1.0L/100km lower than before.

These improvements are also reflected in the entry-level 1.8 TFSI engine, which now produces 125kW/320Nm while consuming as little as 5.7L/100km. These amount to improvements of 7kW and a substantial 70Nm over the old version, while consuming 1.4L/100 km less fuel.

The final engine in the range – a supercharged 3.0-litre V6 petrol – is available in two states of tune, the 200kW/400Nm 3.0 TFSI quattro (from $93,400) and the flagship 245kW/440Nm quattro S4 (from $120,400).

The first therefore gets a 5kW/70Nm increase over the 3.2 FSI it replaces for a 0-100km/h time of just 5.4 seconds – a full second faster than before – coupled with fuel consumption improved to the tune of 1.2L/100km to 8.1L/100km.

The stonking S4 power figures are unchanged from the previous model, but fuel use on the sedan has been cut from 9.4L/100km to 8.1L/100km (8.4 for the Avant). The standing sprint time is 5.0 seconds (or 5.1 for the wagon).

Audi reports that the Avant accounts for half the initial order bank for the revised S4, even though wagons account for only 15 per cent of total A4 sales in Australia.

All A4 sedans have a luggage capacity of 480 litres, while Avants accommodate 490 litres expanding to 1430 with the rear row of seats folded.

Standard safety equipment on all models includes dual front, side, curtain and head airbags, Attention Assist, ESC, Brake Assist and an electromechanical parking brake.

Base variants get standard 17-inch alloy wheels, rear parking sensors, fog lights, climate-control, automatic headlights and wipers, multi-function leather steering wheel, faux leather seats, eight-speaker sound system with 6.5-inch touchscreen, Audi music interface and Bluetooth phone and music streaming.

2.0 TFSI and 3.0 TDI variants get larger alloy wheels, keyless start, front sensors, Xenon headlights with LED daytime-running lights, paddle shifters, electric seats, higher grade sound system and satellite-navigation.

Further up the model tree, the 3.0 TDI quattro and 3.0 TFSI quattro get genuine ‘Milano’ leather seats, while the flagship S4s add a larger 7.0-inch screen, adaptive cornering headlights, better-bolstered bucket seats and lowered Sports suspension.

The S4 Avant also gets unique features including aluminium roof rails and an electric tailgate.

A vast number of options are also available, most notably the $900 Assistance Package ($1900 on entry 1.8 TFSI and 2.0 TDI variants) that adds Adaptive Cruise Control, Active Lane Assist and front and rear parking sensors.