Audi S8 vs BMW Alpina B5

What's the difference?

The S8's existence is a source of joy for me because it's not a huge SUV. Yes, it's a huge sedan but it's a reminder that the technological flagship is alive and well, at least in Germany. And the important thing about these cars is the way the toys filter down through the rest of the range. That used to take years but we're seeing this cool stuff a lot more quickly, right down to the A1.

The S8 punches, and punches hard in this rarefied part of an already shrunken section of the market - the twin-turbo V8 matches its German rivals, it's lighter and it's as well-stacked as any of the three. What it doesn't do, however, is shout about itself the way the other two do.  It's the incognito choice.

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.

The sheetmetal is obviously very restrained given it's an Audi first, and secondly, it's just not done to go wild in this part of the market.

It's an A6 that's joined a gym, but didn't join that weird gym with men that can't run after you when you insult them (don't ask how I know this). Rolling on 21-inch wheels as standard, you can go up to massive 22s if you so choose.

The A8 created a subtle redirection of Audi's passenger car look, with the updated A4 and A6 both picking up on the horizontal bar between the rear lights and the huge grille framed by family lights with signature DRL patterns. The S8 builds on that with subtle S cues but nothing even vaguely shouty.

The interior acreage - or 'cabin', if you will - is very comfortable, but you already knew that. The multi-screen layout was first seen in the A8 and has now found its way into A7, Q8 and Q7 and is, as ever, brilliant to look at and use.

The MMI updates that have found their way into other cars are present and correct. Like the exterior, it's very restrained but not to the point of sparse minimalism, despite the lack of switches and buttons.

I really don't like the steering wheel, though, and I can't put my finger on why. It certainly isn't especially sporty-looking but I wonder if the standard flat-bottomed S wheel just looked stupid.

The materials are beautiful and everything fits together perfectly.

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.

The cabin is clearly built with rear seat passengers in mind, with rear leg and headroom configured for those continent-crossing drives.

The S8 has plenty of comfort for two rear seat passengers and a few amusing options to while away the hours in traffic or on the autobahn.

That doesn't mean the front seat passengers are in purgatory, with huge but supportive seats adjustable in all conceivable directions.

Front and rear rows score a pair of cupholders and bottle holders while the boot is a handy, if not awe-inspiring, 505 litres.

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).

Under that long bonnet is a 4.0-litre twin-turbo V8 pumping out 420kW and a diesel-like 800Nm of torque. 

That's a lot, even for this big bruiser. Obviously, being an Audi S-car, it has quattro all-wheel drive, which is fed by an eight-speed ZF automatic. Which is in everything now. Well, just about.

That huge torque figure is available between 2000rpm and 4500rpm while peak power arrives at 6000rpm. The 0-100km/h sprint is despatched in - gulp - 3.8 seconds.

As it's riding on the MLB platform, the mild hybrid system is a 48-volt set-up. A lithium-ion battery in the boot takes charge from the belt alternator/starter, which means the S8 can coast at higher speeds with the engine off and also cut out at 22km/h and under in traffic.

The system can also add up to 60Nm of torque in the right conditions for up to six seconds, and if it happened for me, I didn't notice it.

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 10.5L/100km official figure is, shall we say, optimistic. The launch drive was mostly highway so there's no real information to be gleaned from that, so we'll have to wait for real world fuel figures.

I'd say 12-13L/100km is achievable if you don't like having fun, in which case, the lesser A8 is probably for you.

Audi says the MHEV system saves 0.8L/100km with an early cut-out for the stop-start and the ability to coast on the highway for over half a minute at a time.

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.

Driving any of the cars in this segment is a rare treat, whether it's the 'entry level' diesel or this top of the heap sports sedan. My day with the S8 was filled with the usual surprise and delight that only these tech-packed cars can deliver.

Heading out of the Sydney CBD in 'Comfort' mode, the car scans the road ahead and adjusts the active suspension accordingly. You already know it has active suspension because when you pull the door handle, the car lifts by 50mm to make it a bit easier to get in.

The suspension's party trick is flat-topped speed bumps - drive at one, brake a little and sense the way the body feels like it stays exactly where it is in the air but the suspension almost completely flattens the speed hump.

It's uncanny and almost unnatural, with just the tiniest change in altitude and no noise from the suspension.

It also manages the terrible narrow lanes of CBD thoroughfares with ease, the lane keep system letting you know if you're straying.

On to the motorway and you get a feel for its crushing performance. You won't hear much, though - the stereo's noise-cancelling system shuts out almost all tyre noise and consistent wind noise is largely banished, too.

I'm going to admit I gasped when I found some corners. Active suspension bodes well for the tricky stuff, as does the all-wheel steering. Both are exceptionally clever systems for making the car feel a lot smaller in town and in car parks but they're also really good if you want some fun.

But the way the rear-wheel steer adds agility to such a big car is hilarious and clever. While you can't quite chuck it around - and really, you're not buying an A8-sized car for that kind of nonsense - brisk progress is far from intimidating.

Now, obviously, a Ford Fiesta would drive away from the S8 in the really tight stuff but it would take some time to properly shake it. The colossal torque from the V8 hurls even this two-tonne-plus limo out of the corners in a most satisfactory manner.

It's surprisingly agile for a machine more than five metres long and two metres wide. If your passengers are corner enthusiasts, you'll all be having fun in near silence. It's oddly engaging to be moving at pace in such a hushed cabin.

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.

Audi continues to fail to match Mercedes move to a five year warranty, sticking with three year/unlimited kilometre cover. BMW is still doing it too, so maybe Ingolstadt and Munich are playing chicken. 

You can get a five-year service plan for the S8, coming out at $3990 for the duration.

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