BMW Alpina B4 vs Audi S5

What's the difference?

You could almost call the B4 S the anti-M4. It's still fast and practical but from a completely different perspective. It's much more a grand tourer than the M4 and even with the Akrapovic exhaust (usually a byword for joyous, anti-social racket), subtle.

For some, the price won't matter because the Alpina delivers what they want - M4-like straight line performance without the histrionics or the uncompromising chassis. And there's also a bit of that perverse exclusivity of the styling that you won't get anywhere else.

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.  

Alpina has always had a particular aesthetic that could uncharitably be termed as mid-'80s West German - all set square angles and body graphics. Think David Hasselhoff's Berlin Wall look. The company has never really deviated from adding squared-off body bits to the various BMWs it has rebadged under its long-running agreement.

For the B4S, Alpina adds the signature billion-spoke alloy wheels (only a slight exaggeration), a new front splitter complete with Alpina lettering, a weirdly proportioned boot lid lip spoiler and - not even joking - pinstripes. Like I said, mid-'80s West German. You can still recognise the sleek 4 Series Coupe but perhaps the worst of it is the super-sized, wonky-looking ALPINA B4S on the boot.

Inside is rather more restrained apart from the ill-fitting Alpina plaque under the climate control. Again, it's all 4 Series in here, with the lovely Merino leather liberally applied across the cabin. Less lovely is the wood on the door pulls and console but the door cards have an oddly appealing woven leather which looks and feels good.

Sadly the standard 4 Series steering wheel is along for the ride. There's nothing wrong with it - although the Alpina logo does look out of place - but if I were a product planner, I'd beg for the lovelier M wheel.

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.

If you're in the front, you're in luck - it's a comfortable place to be, with plenty of leg and headroom. Down back isn't terrible despite the coupe roofline. The two seats are nicely shaped for maximum comfort and separated by an odd plastic tray. The fold-down armrest has two cupholders.

Front seat passengers score a pair of cupholders (bring the total to four for the car) and the long doors will hold a bottle each.

The boot swallows a reasonable 445 litres, which isn't at all bad.

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.

A lot of your extra money turns up under the bonnet. These days the 440i packs BMW's slick B58 turbo straight six and the B4S does likewise. The boys from Buchloe in Bavaria (there are certain to be women there, too, I just liked the alliteration) added a pair of Alpina-spec turbos to generate a whopping 324kW and, more importantly, 660Nm. Alpina says 600Nm (the max torque figure of the brilliant M4 CS) is available from 2000-5000rpm, while the full 660Nm is available from 3000 to 4500rpm.

The M4 Pure has 317kW and 550Nm from the S55 straight-six. Just so you know.

Like the 440i but unlike the M4, the B4S employs the dependably brilliant eight-speed ZF automatic found throughout the BMW range.

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. 

Alpina quotes 7.9L/100km on the combined cycle and we went through the premium unleaded at the rate of 11.7L/100km. I enjoyed myself, so that's not a terrible result.

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.

One of the key differences between the B4 and M4 is the ride. While the M4 can crash over bumps and generally be a little hard to live with, the crew in Buchloe have gone after a much more plush ride. And in that they have succeeded because the B4 S is a mighty fine cruiser. Bumps are dismissed with a haughty disdain, even Sport + silliness doesn't completely write-off ride quality.

Very impressive too, is the steering. While still not at Lotus Elise levels of feel (few cars are), the Alpina tweaks connect the your palms to the road with more clarity than what you'll find in the 440i or M4. Where the M4 particularly adds too much weight, the 440i is a bit more circumspect in that regard.

And then we come to the engine. The B58 six is a belter, better even than the N55 that preceded it. It's still a 3.0-litre straight six but is part of BMW's modular engine family that starts with a 1.5-litre triple in the Mini and 1 Series. The Alpina-spec turbos are noisier, the Akrapovic exhaust lighter and also noisier. It doesn't have the all-out crackle and pop of an Audi or Merc (perish the thought), but when you're on it, the B4 means business. The 660Nm of torque, available over a wide rev range, delivers a steel fist wrapped in a velvet glove and bubble wrap - the speed builds rapidly but smoothly. 

The approach to the chassis tune seems to be based on the driving talents of mere mortals on normal roads, which is kind of like the 440i. It's terrific fun to drive hard but it's very forgiving and patient. The great thing about it is that you wouldn't think twice about jumping in it for the long haul, so comfortable and quiet is the cabin. The M4 will leave it for dead on a winding road, but that's perfectly fine.

One irritant is the replacement of the admittedly cheap BMW gearshift paddles with weirdly non-tactile buttons. They're not particularly easy to use and, probably worse for a sporty car, unsatisfying. It's an odd detail with which to go off the reservation. Cheeringly, the eight-speed ZF is its usual perfect self, so you don't have to worry too much about manual mode or go old school and use the shifter.

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.

Alpina offers a two-year/unlimited-kilometre warranty which is a bit behind the times and not in keeping with the price point. Servicing is another matter altogether and you're subject to your dealer's standard charges for servicing.

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.