BMW 320d vs Audi S4

What's the difference?

Despite BMW's wholehearted embrace of the SUV its 3 Series is still a critically important model for the brand in Australia. And this new version certainly has the spec and tech to take the fight up to Merc's C-Class. And if you're in the happy position of making that choice, it's now a whole lot harder. For our money the 330i marks the sweet spot with extra performance, safety tech and standard features for only a fraction more than $3k over the 320d entry-point.

The S4 and S5 range continues to represent a great formula for performance you can live with every day. They're arguably the sweetest balance Audi produces, actually. All come fantastically equipped, with cabins that feel truly special, and we’re lucky they can be had in a choice of five bodystyles.  

At just over 4.7m nose-to-tail the new 3 Series has crept 76mm in overall length but that dimension is still more than 200mm shy of its next-size-up 5 Series sibling.

Changes to the exterior design are more evolutionary than revolutionary. You're never going to mistake this car for anything other than a BMW 3 Series.

But even if the face is familiar, aerodynamic efficiency is outstanding. BMW admits its claimed Cd of 0.23 was achieved with a base model running on 17-inch wheels (not offered here), but even if bigger rims knock a few fractions off that number it's still an amazing result for a conventional four door sedan.

Big contributors are a full width front spoiler, 'air curtains' managing flow around each corner of the nose, almost complete sealing of the largest areas underneath the car, and a functional rear diffuser section.

The signature kidney grille has grown and is delivered as a single piece, with active shutters incorporated to manage cooling air flow through to the engine. Twin adaptive LED headlights (standard on all models) feature a sharp notch on their lower edge, a big clue for new model spotters.

Broad, carefully managed surfaces characterise the bonnet and flanks of the car, with a distinct character line just above door handle height enhancing its confident stance.

The slightly smoked L-shaped LED tail-lights sit proud of the body, and 18-inch alloys are standard on the 320d, stepping up to 19s on the 330i.

The interior has been redesigned with revised controls and new materials, including slick 'aluminium teragon' finish on the console and dash in the M Sport.

As you can see in our interior images, it's been tidied up and simplified considerably, although it will still be instantly recognised by current BMW drivers.

Highlights are a 12.3-inch configurable digital 'Live Cockpit Professional' instrument display (lifted directly from the X5), a new 10.25-inch media touchscreen and a standard (larger) head-up display.

The S4 sedan and Avant have scored the bulk of design updates, with all new and recontoured side panels including the sedan’s C-pillar matching what was applied to the A4 earlier this year. 

This is paired with new front and rear facias and lighting for a subtle but extensive rework of the fifth-generation S4’s conservative look. 

The S5 Sportback, Coupe and Cabriolet get S5-specific new lighting and facias, but no sheetmetal changes. As before, the Coupe and Cabriolet ride on a 60mm shorter wheelbase than the Sportback, sedan and Avant.

The S5s also get Matrix LED headlights as standard which do a neat animated sequence when you unlock the car. 

Other visual hallmarks include new S4-specific 19-inch wheels, with S5 stepping up to its own unique 20-inch wheel. The six-piston front brake calipers are appropriately painted red, and there’s S-specific adaptive dampers under there too. All variants aside from the Cabriolet get a lip spoiler on the rear.

On the inside, there’s a new centre console and bigger 10.1-inch multimedia screen, while the Audi Virtual Cockpit driver instrument display now offers a hockey stick-style rev counter in additional to traditional dial layouts.

A longer wheelbase (+41mm) has helped increase overall cabin space and rear room specifically.

There's plenty of storage provided with a large lidded box between the front seats as well as two large size cupholders in a recessed section in front of the gear shift (which can be closed off with a roll-top style cover).

The glove box is large and there are big bins in the doors with separate holders for full-size bottles.

Rear legroom is generous. At 183cm, sitting behind my own driving position, there was plenty of fresh air between knees and seatback, with lots of foot room to boot.

Headroom was more marginal with a straight back leading to a bonce/roof interface. But there are adjustable rear vents, twin cupholders in a fold-down centre armrest, and big bottle holders in the doors. Multiple USB ports (Type A and Type C) and a 12-volt power outlet are provided front and rear.

The boot space offers up a 480-litre luggage capacity with a 40/20/40 split-folding rear seat increasing cargo flexibility. Local towing capacity is yet to be confirmed, but indicative (European) ratings for both models are 750kg for an unbraked trailer and 1600kg braked.

Standard rubber is run-flat so there's no spare of any description.

The biggest practicality change among the five S4 and S5 variants is their upgrade to the latest version of Audi’s MMI multimedia system, which steps up to a 10.1-inch touchscreen and drops the scroll wheel from the centre console.

It also boasts ten times the computing power of the version it replaces and uses this and an on-board sim card to access Google Earth maps for navigation and Audi Connect Plus that offers driver information such as fuel prices and parking information as well as point of interest search and weather information, plus the ability to make emergency calls and seek roadside assistance.

There’s also a wireless phone charger, but using Apple CarPlay will still require a cord as per Android Auto.

I only drove the S4 Avant and S5 Sportback at their media launch, which are clearly the most practical of the five, but from our experience with the previous versions, each looks after its occupants well in terms of space and storage. Back seat accommodation is clearly not a priority in the Coupe and Cabriolet, but there’s three other variants if that’s what you’re looking for. 

The Cabriolet can open its automatic folding soft top within 15 seconds, at speeds of up to 50 km/h.

As I mentioned above, the S4 and S5 line-up are in many ways the same, but also different, and these differences result in a price span of $20,500 between the S4 sedan and the S5 Cabriolet. 

The former is now $400 cheaper with a list price of $99,500, with the also-$400 cheaper S4 Avant not far beyond at $102,000.

The S5 Sportback and Coupe are now $600 more expensive at an equal list price of $106,500, while the swish folding soft top of the S5 Cabriolet pushes it up to $120,000 (+$1060).

Equipment levels are consistent across all five variants aside from the S5s getting Matrix LED headlights as standard and one inch larger 20-inch wheels. 

Key details include Nappa leather trim with front sport seats with seat heaters and massage function, a Bang & Olufsen sound system which spreads 755W across a total of 19 speakers, brushed aluminium inlays, head-up display, coloured ambient lighting, tinted windows and metallic paint.

Over the past 12 months, the S5 Sportback has proven to be the most popular of the five variants by far, accounting for 53 per cent of sales, with the S4 Avant next in line at 20 per cent, the S4 sedan making up 10 per cent, and the S5 Coupe and Cabriolet combining to make up the remaining 17 per cent.

The 320d is powered by a 2.0-litre four-cylinder twin-turbo-diesel, featuring common-rail direct-injection and variable inlet timing. It produces 140kW at 4000rpm and 400Nm between 1750-2500rpm.

The turbo's multi-stage design incorporates a small, high-pressure, fixed-vane turbocharger as well as a larger, low-pressure, variable-vane turbo to maximise response, performance and efficiency.

A 2.0-litre single turbo-petrol four-cylinder engine sits under the 330i's bonnet incorporating direct-injection, as well as variable valve and cam timing. Peak outputs are 190kW from 5000-6500rpm and 400Nm between 1550-4400rpm.

Mark the date because this is the first time the BMW 3 Series has been offered in Australia without a manual gearbox option. Both launch models send drive to the rear wheels via an eight-speed automatic (with wheel-mounted shift paddles) only.

Audi has taken an ‘if it ain’t broke’ approach with the mechanicals, with all S4 and S5 models unchanged with this update. So the centrepiece continues to be the single-turbocharged 3.0-litre V6 that produces 260kW and 500Nm, with the latter available from a broad 1370-4500rpm.

The rest of the drivetrain is also unchanged, with the venerable but excellent ZF eight-speed torque converter auto paired with the Quattro all-wheel drive system that can send up to 85 per cent of drive to the rear wheels. 

Despite each car's performance potential claimed fuel economy for the combined (ADR 81/02 - urban, extra-urban) cycle is commendably low.

BMW says the 320d delivers excellent diesel fuel economy, consuming a miserly 4.5L/100km, emitting 119g/km of CO2 in the process, with the 330i's fuel consumption figure coming in at 6.4L/100km and 147g/km.

You'll need minimum 95 RON premium unleaded in the 330i, with both petrol and diesel requiring 59 litres to fill the tank to full capacity.

Official combined fuel figures range from 8.6L1/00km for the S4 sedan to 8.8L/100km for the Avant, Coupe and Sportback, while the heavier Cabriolet steps up to 9.1L/100km. 

All are pretty good considering their performance potential and the size of these cars, plus the fact that they only require 95 RON Premium Unleaded fuel.

All have a 58-litre fuel tank, which should enable a range of at least 637km between fills based on the Cabriolet’s figure.

First, the performance figures. BMW claims the 320d will accelerate from 0-100km/h in 6.8sec, which is agreeably quick, while the 330i knocks that down to 5.8sec, which is properly fast.

Both engines deliver the same 400Nm of maximum torque at low rpm; 1750-2500rpm for the 320d, and a broader 1550-4400rpm spread for the 330i. Mid-range acceleration is strong and satisfyingly linear in each, the 330i that bit more urgent at the top end.

The eight-speed auto is velvety smooth, with the wheel-mounted shift paddles on hand for rapid 'manual' changes. Engine noise is muted at low revs but nice and rorty under pressure.

A stated aim in the development of this 3 Series was "dynamic engagement", and the standard strut front, multi-link rear suspension has been tuned to reinforce the driving part of the brand's long-standing 'ultimate driving machine' promise.

The standard suspension includes tricky two-stage dampers front and rear, but with all cars at the local launch fitted with the optional active damper system we'll have to wait to report on its quality (or otherwise).

This car's centre-of-gravity is 10mm lower than the model it replaces, which may not sound like much, but in engineering terms, absolutely is. In concert with a perfect 50:50 front-to-rear weight distribution, and wider tracks front and rear, it helps deliver an overall planted feel and predictable cornering balance.

The electro-mechanically assisted steering is accurate and linear with good road feel, which is not always the case in recent Beamers.

The launch fleet was also rolling on 19-inch rims (standard on 330i, optional on 320d) shod with Bridgestone Turanza run-flat rubber (225/40f - 255/35r) and despite that type of tyre's reputation for harsh characteristics and a moderate level of road noise, ride comfort on the typically coarse rural roads we covered in the Victorian high country was impressive.

Braking on both models is by ventilated disc front and rear, and even in spirited cornering maintained their power and efficiency. The M Sport brake package fitted to the 330i dials things up with four-piston alloy calipers (sourced from Brembo) up front.

The standard sports steering wheel is fat and grippy, the sports front seats combine firm location with long-distance comfort and overall noise levels are low. Overall, this is a super-impressive touring car.

The S4 and S5 range were already an excellent balance between everyday comfort and a genuine sporting edge, and nothing has changed with this update.

I spent time behind the wheel of the S4 Avant and S5 Sportback at their media launch, and both managed to deliver the proper Audi luxury experience over some pretty rough rural roads, while always feeling a bit more sporting than a regular A4 or A5. That’s with the Drive Select left in the default mode, but you can shift that sporting personality up a few notches (while scaling back the comfort), by selecting Dynamic mode. 

My preferred means of adjusting their personality is by simply tugging the transmission selector back to activate S mode, which livens up the engine and transmission without stiffening up the suspension. 

Across the five S4 and S5 bodystyles, there is some variance in performance potential, with the S4 sedan and S5 Coupe topping the performance chart with 0-100km/h boasts of 4.7s, with the S5 Sportback trailing them by 0.1s, the S4 Avant by a further 0.1s and the Cabriolet managing a still-fast 5.1s claim.

Another area I consider the S4 and S5s to get just right is their exhaust note. It is adaptive, but there’s nothing synthetic about it, and the generally muted and distinctly V6 burble is always there to remind you that you’re aboard a proper performance model, but not in such a way that it will annoy you, or your neighbours. Polite performance, if you will.

All S4 and S5 variants boast an impressive array of safety features, but there’s some interesting points when it comes to ANCAP ratings. Only four cylinder A4 models (therefore not S4) were given a maximum five star rating when tested according to less stringent 2015 standards, but all A5 variants (therefore S5) aside from the Cabriolet carry a five star rating based on the tests applied to the A4. So officially, the S4 is not rated, but the S5 Coupe and Sportback are, but based on the A4 rating that doesn’t apply to the S4. As with most convertibles, the Cabriolet is simply not rated. 

The airbag count totals eight in the sedan, Avant and Sportback, with dual front airbags, plus side and curtain airbags covering front and rear.

The Coupe drops the rear side airbags, while the Cabriolet also drops curtain airbags, meaning there’s no airbags for rear seat occupants. The roof is made of folding fabric, there has to be some safety compromise.

Other safety features include front AEB that works up to 85km/h, adaptive cruise control with traffic jam assist, active lane guidance and collision avoidance assist that can automatically swerve, a 360 degree camera system, rear cross-traffic alerts, exit warning that can prevent you opening a door into an oncoming car or cyclist, and pre sense rear that can detect an impending collision from behind and prepare the seatbelts and windows for maximum protection.

BMW offers a three year/unlimited km warranty, which is drifting off the pace now with the majority of mainstream brands stepping up to five-year cover, with some at seven.

On the upside, bodywork is covered for 12 years, the paint for three, and 24-hour roadside assistance is complimentary for three years.

Servicing is condition based, so the car tells you when maintenance is required, and BMW offers a range of service packages in 'Basic' and 'Plus' grades up to 10 years/200,000km.

Audi continues to offer a three year, unlimited kilometre warranty, which is in line with BMW but lags behind the five years offered by Mercedes-Benz these days. This also contrasts with the five year norm among mainstream brands, which is punctuated by the seven year warranties of Kia and SsangYong.  

Service intervals are a convenient 12 months/15,000km though, and the same five year ‘Audi Genuine Care Service Plan’ offers capped price servicing for the same $2950 total over five years applies to all S4 and S5 variants. This is only marginally more than the plans offered for regular petrol A4 and A5 variants, so you’re not being stung for the thoroughbred versions.