Audi S6 vs BMW Alpina B5

What's the difference?

We adore the new S6 sedan. It looks great, feels comfortable and goes like stink all at the same time. What’s not to like?

It also helps that it is relatively good value, safe and practical by large-sedan standards, so it’s a bit of a no-brainer.

But will buyers be quick to dismiss the new S6 sedan because it’s not a more practical SUV? Time will tell, but we hope not.

Does the new Audi S6 sedan represent the best mix of executive style and boy-racer performance? Tell us what you think in the comments below.

The Alpina B5 is a special car – more special than most people will ever give you credit for if you own one. Those that do know what an Alpina is will let you know; people will cross dangerously busy streets to talk to you about your car. Insanely fast, almost incomprehensibly comfortable and effortlessly powerful to drive.

To these eyes, the new S6 sedan is very attractive, albeit not outlandish, in keeping with its executive focus.

Up front, the subtly aggressive S body kit immediately comes into frame, with the bumper sporting sinister-looking side air intakes.

And, of course, there’s Audi’s signature Singleframe, which is not only large and in charge, but also finished in gloss-black, like many of the S6 sedan’s exterior design elements.

Below the heavily creased bonnet, the HD Matrix LED headlights look both angry and sophisticated, with their integrated LED daytime running lights (DRLs) providing a crisp signature.

Around the side, the S6 sedan goes about its business quietly, but its blistered wheelarches do add some bulk and help to accentuate its strong shoulder line.

And then there are the thick skirts and 21-inch alloy wheels (with a space-saver spare), which have a sporty twin five-spoke design. It’s all very classy.

Speaking of which, the rear end is arguably the S6 sedan’s best angle thanks to its wicked LED tail-lights, which have a segmented signature.

The chunky bumper below incorporates a diffuser element that houses the quad exhaust tailpipes, while a blink-and-you’ll-miss-it bootlid spoiler rounds out the look.

Inside, the S6 sedan is a technological tour de force, with 10.1- and 8.6-inch touchscreens dominating its centre stack. The former is responsible for most of Audi’s latest multimedia system’s functions, while the latter takes care of the climate controls.

This set-up works pretty well, although a few too many taps are required for certain functions, and then there’s the issue of the glass display coverings, which are absolute fingerprint magnets alongside the gloss-black accents used throughout.

That said, the 12.3-inch digital instrument cluster and windshield-projected head-up display on hand are brilliant. In fact, they set the standard for the entire industry thanks to their design and breadth of functionality.

The S6 sedan does, of course, feel a little bit more special than the regular A6 inside, with the obvious additions being the front sports seats, which are covered in supple Valcona leather alongside the armrests. They even have diamond-stitched inserts.

Then there’s the obligatory flat-bottom steering wheel (with paddle-shifters), which is trimmed in Nappa leather alongside the gear selector, upper dashboard, door shoulders and knee rests. Indeed, hard plastics are hard to find here.

Meanwhile, a black headliner adds to the sportiness alongside the black Alcantara door inserts, but the cabin is otherwise a familiar (read: classy) affair.

Interesting is the right word for it, because while it might be questionable that Alpina's changes to the exterior are aesthetic pleasing, they are definitely intriguing to those who aren't familiar with the brand.

First, there are those 20-spoke wheels. Alpinas have worn this style of wheel forever and they've become the most famous outward sign that this is not just another BMW. So don't under any circumstances take them off and replace them with anything else. You'd be run out of town by the Alpina mafia.

Yes, they're more painful to clean than a cheese grater (trust me, I know. And if you look closely at these images you can see the dirty bits I've missed), but if you really don't like them then perhaps it's a sign this car isn't for you.

Then there's the boot-lid spoiler. It's square and 1980s'-looking, it also appears a bit like it's been bought online and installed by a teenager, but again, this is another Alpina tradition and it suits the car's character perfectly.

All right, those pinstripes; they're known as the Deco-Set and are a hat-tip to the Alpina racecars of the 1970s and '80s. Again, don't take these off, your Alpina will drop through the centre of the Earth in value. These are also part-and-parcel of owning one of these cars. I'm not a massive fan of them.

But I'm all about that front spoiler, with the floating Alpina lettering that you can option in silver, high-gloss black or gold.

Inside, there are fewer Alpina additions, but they're nonetheless unmissable. There's the Alpina-badged steering wheel, and a new virtual instrument cluster, embossed headrests and  illuminated door sills.

There's also the little numbered plaque on the centre console which proves its authenticity, ours was number 49. Out of how many? I don't know. But I do know Alpina produces only about 1700 cars globally a year. Rolls Royce does about 4000. So, you can rest assured your B5 is exclusive.

At almost 5m long, 1.9m wide and 1.5m tall, the B5 is a large saloon, but having recently reviewed the Alpina B7 it feels small in comparison. How does it drive? We're getting there.

Measuring 4954mm long, 1886mm wide and 1446mm tall, the new S6 sedan is a large sedan in every sense of the term, which is mostly good news when it comes to practicality.

Cargo capacity is decent, at 520L, but can be increased to an undisclosed amount with the 40/20/40 split-fold rear bench stowed.

Speaking of the boot, there are four tie-down points and a cargo net to help secure loose loads, while a bag hook and a side storage net are also on hand, alongside a 12V power outlet. Bulkier items will, however, be confronted by a decent load lip.

In-cabin storage options are numerous, but not all are effective. The glovebox is well-sized, while the driver-side cubby is surprisingly large, but the central bin is shallow, mostly taken up by the wireless smartphone charger, two USB-A ports and the SD and SIM card readers.

A pair of cupholders is located in the centre console, with a 12V power outlet found in between, while the front door bins can accommodate one regular bottle each, just like their rear counterparts.

In the second row, there’s a fold-down armrest with two more cupholders as well as a shallow storage tray, while cargo nets are affixed to the front seat backrests.

The rear bench is pretty comfortable, with four inches of legroom available behind my 184cm driving position alongside decent toe-room. Headroom is also good, with about two inches on offer.

That said, three adults sitting abreast won’t enjoy the experience, due to the large transmission tunnel, which makes for limited footwell space. At least they’ll have access to a couple of USB-A ports and a 12V power outlet, below the central air vents.

For reference, child seats can be fitted to the outboard seats via top-tether and ISOFIX anchorage points.

Practicality is not really a BMW strong point no matter which model you pick. See, BMW mostly makes the car equivalent of uber-stylish and skin-tight active wear which looks good and performs brilliantly, but sometimes you just want pockets and a bit of room for your… um… bits and pieces.

So while there are two cup holders up front and two in the back, the bottle holders in the doors aren't huge, the centre console bin is on the small side, there's a hidy-hole in front of the shifter, the glove box is just a box for little more than gloves and there's no other great cabin storage options.

Legroom in the rear is good but not great, too - I'm 191cm tall and have about 30mm between my knees and the seat back in my driving position. Middle-seat passengers will also have to straddle the drive shaft hump in the floor. Headroom is restricted in the back, too (you could blame the sunroof) with my hair just skimming the headlining (I do have big hair).

Under that power tailgate, the B5's boot capacity is 530 litres which is 15L more than its big sister, the B7. There are two plastic storage areas either side of the luggage space for wet things. While there is one USB outlet in the front there aren't any in the rear.

The BMW Alpina B5 lists for $210,000, making it only $10K more the BMW M5 which comes with almost identical features apart from the Alpina engineering to the engine and chassis.

Arriving standard is leather upholstery, four-zone climate control, nav, the Alpina embossed-headrests, a 10.25-inch display, digital radio, Alpina door sills, sunroof, proximity key, power front seats, 12-speaker Harman Kardon stereo, head-up display, Alpina virtual instrument cluster, heated front and rear seats, and the 20-inch Alpina wheels.

The test car I drove had been optioned with a limited-slip differential ($5923), steering-wheel heating ($449); soft-close function for doors ($1150); sunblinds ($1059); TV function ($2065) ambient air package ($575), and front-seat ventilation ($1454).

The new S6 sedan is powered by a hard-hitting 2.9-litre twin-turbo V6 petrol engine that produces a strong 331kW of power from 5700-6700rpm and a punchy 600Nm of torque from 1900-5000rpm.

Compared to its aforementioned predecessor, power is unchanged, while torque has increased by 50Nm.

This unit is mated to a 48V mild-hybrid system that includes a trick Electric-Powered Compressor (EPC), which helps to reduce its turbo lag.

A reliable eight-speed torque-converter automatic transmission is responsible for swapping gears, while drive is sent to all four wheels via Audi’s rear-biased quattro system.

This combination helps it sprint from a standstill to 100km/h in an impressive 4.5 seconds, while its top speed is electronically limited to 250km/h.

The Alpina B5 uses the same 4.4-litre V8 engine found in the BMW M5 (and also the B7). But, and it's a big but, the M5 makes 441kW and 750Nm, while the B5 outdoes it with 447kW and 800Nm. Admittedly, the B5's torque arrives at the 3000rpm mark, while the M5's is all there from 1800rpm.

How does the B5 beat it? Alpina installed its specially developed twin turbochargers and intercoolers, a high-performance cooling system, a reconfigured air intake set up and a different exhaust system.

The B5, though, is a tenth of a second slower to 100km/h compared to the M5 with a time of 3.5 seconds, but it will blast on to a top speed of 330km/h while the M5 is limited to 250km/h in regular form and 305km/h with the optional M Driver's package.

Both uses the same ZF eight-speed automatic transmission with identical gear ratios, and both are all-wheel drive.

The new S6 sedan’s fuel consumption on the combined-cycle test (ADR 81/02) is 8.4 litres per 100 kilometres, while claimed carbon dioxide emissions are 197 grams per kilometre. Both figures are pretty keen given the level of performance on offer.

Audi says the aforementioned 48V mild-hybrid system reduces fuel consumption by 0.4L/100km thanks to its coasting ability, which sees the engine turn off for up to 40 seconds between 55km/h and 160km/h. It also engages idle-stop from 22km/h.

In our real-world testing, we averaged 14.4L/100km over 100km of driving skewed towards country roads over city traffic, with limited highway time. It’s worth noting that my spirited driving inflated this result. That said, while its fuel consumption is not as bad as it appears, this is still a thirsty sedan.

For reference, the S6 sedan’s 73L fuel tank takes 98RON petrol at minimum.

The Alpina B5 needs petrol. By that, I mean it needs quite a lot of it if you want to enjoy it properly. What type of mileage does it get? Officially, it should use 11.1L/100km after a combination of urban and open roads, where as the M5 is set to 10.5L/100km.

That makes sense, the B5 produces more power and torque, and it's 85kg heavier than the M5 at 2015kg.

Our test car's trip computer was reporting 13.2L/100km after flying low over country roads and slow city piloting. The more time spent in the urban warfare that is the daily peak hour commute, the more that figure crept and hovered around the 15L/100km mark.

The S6 sedan has no right being this good in a straight line and around corners…

Much of its success is owed to the 2.9-litre twin-turbo V6, which is now one of my favourite engines being built today. Simply put, it absolutely hammers.

Punch the accelerator from a standing start and it doesn’t take long for 600Nm to be on tap all the way through, and just a little bit beyond, the mid-range.

Occupants are firmly pressed into their seats as the S6 sedan sprints towards the horizon with vigour. Soon enough, 331kW arrives and hangs around until just prior to the redline.

Needless to say, this acceleration is addictive, and the EPC deserves some of the credit, as it effectively mitigates any dreaded turbo lag and ensures the engine is always seemingly on boost.

But we also need to acknowledge the eight-speed torque-converter automatic, which is a real beauty. Gear changes are nice and smooth, which is great, but what’s even better is their relative quickness – dual-clutch transmissions be damned!

Of course, extra performance can be extracted by switching between the engine and transmissions’ settings but, rest assured, they both stand up, no matter what.

However, we’d suggest spending time in the former’s most aggressive setting, as it unleashes the sports exhaust system, which sounds unreal.

Upshift with intent and you’re met with a booming ‘brap’. Downshifts and the overrun will even gift you a series of pops. In fact, the S6 sedan soundtrack sounds strangely similar to that of the five-cylinder RS3, and we have absolutely no problem with that.

Better yet, the S6 sedan has an appetite for corners, with its neutral handling a standout, partly thanks to its hard-working rear-biased quattro all-wheel-drive system, which works in tandem with all the other electronics to ensure there is plenty of grip at any given time.

This controlled driving pleasure is enhanced by the electric power steering on hand, which has a variable ratio. At low speed, it’s nice and light, but those after more heft can always switch to another one of its settings, which become progressively heavier… arguably too heavy.

Feedback through the wheel is also good, while the steering itself is pretty direct, lending itself to sporty driving, which, of course, is half of the S6 sedan’s mantra.

Coming into corners, braking performance is solid, thanks to the massive 400mm front and 350mm rear discs with red callipers, so the driver is brimming with confidence at every turn, even though there’s an unladen weight (with 75kg driver and luggage) of 1985kg to manage.

But let’s not forget the S6 is an executive sedan, so it has to ride like one. Thankfully, it does. The independent five-link suspension has air springs and adaptive dampers, which serve up comfort in spades, especially at high speed.

Its firm tune does come into frame when travelling on unsealed or uneven roads, with this exacerbated by the large 21-inch alloy wheels, which have a penchant for catching sharp edges.

Ok, stay with me here. For this next bit you'll need a fresh egg, a lounge chair, and it might be a good idea to have some plastic bags and carpet cleaner on hand.

First, in front of the lounge chair flatten out the plastic bag and place the egg on it. Next, sit down on the chair and very carefully rest the ball of your foot on the egg with as little pressure as humanly possible.

This is exactly how little force you need to apply to the go-pedal of the B5 to accelerate from a standstill to 60km/h in about five seconds.

If anything sums up the driving experience of the B5, it's that sense of effortlessness.

Stomp on that accelerator, and you'll be shot to 100km/h in 3.5 seconds, without a hint of broken traction thanks to the all-wheel-drive system.

The ride should have been terrible on 20-inch wheels shod in low-profile rubber (Pirelli P Zero 255/35 front, and 295/30 rear), but the Alpina-tuned air suspension is close to miraculous in the way it cushioned and censored the potholes out of Sydney's worst roads. Yes, it can be a touch floaty, particularly in the Comfort Plus setting, but this is benchmark-setting stuff for a comfortable ride.

Don't expect this beast to roar. Unlike the M5, the B5 gets its work done without deafening everybody around it. Sure, the B5's V8 sounds amazing when you push it, but it's not brash, not loud and not lairy. Buy an M5 or Mercedes-AMG E63s if you want to be heard half a block before you get home, but you won't get that with the B5 and its exhaust system.

The B5 also handles well, but I have to say the engagement factor is low. I piloted it effortlessly through the twists and turns of my country test circuit and roads which normally have me grinning like a maniac behind the wheel had me feeling a bit disconnected in the B5. That air suspension, the numb steering and pedal actions make it difficult to ‘feel' the road.

It's highways where the B5 is a king, but even at 110km/h there's the sense that this car is still fast asleep and won't get out of bed for anything less than 150km/h - making it perfect for Germany's autobahns, but maybe not for here in Australia.

The Alpina B5 is based on the BMW 5 Series which had a five-star ANCAP rating awarded to it in 2017.

Along with the comprehensive suite of airbags, traction and stability control, there's an impressive array of advanced safety equipment. Coming standard is AEB (front and rear), evasive steering, front and rear cross-traffic warning, blind-spot alert and lane-keep assist. The Alpina B5 also comes with BMW's emergency call function.

For child seats you'll find two ISOFIX mounts and three top tether points across the rear row.

safety

If you're unfortunate enough to get a flat tyre, there's a puncture repair kit in the boot which works provided the hole isn't giant, as I've experience in the past with these systems.

The S6 sedan comes with Audi Australia’s three-year/unlimited-kilometre warranty, which falls short of the premium market’s relatively new five-year standard that was set by Genesis and followed by Mercedes-Benz.

Three years of roadside assistance is also bundled in, although this term can be extended up to nine years if the vehicle is serviced at an authorised dealership, which is great.

Speaking of which, service intervals are every 12 months or 15,000km, whichever comes first. Capped-price servicing plans are available, costing $2350 for three years/45,000km or $4110 for five years/75,000km. They’re pricey, but you weren’t expecting the opposite.

The Alpina B5 is covered by BMW's three-year/unlimited kilometre warranty. Servicing is recommended every 12 months or 15,000km.