Audi A6 Avant

There's something of a 'back to the future' feel here.

For years with the A6, Audi has been trying to match the sharply-responding feel of rival rear-driven BMW 5 Series or Mercedes E-Class models.

Which it was never going to fully do with a fundamentally front-driven-platformed car.

With this C9-era A6 though, the emphasis has returned to something that Ingolstadt is properly good at - exemplary refinement through super-sleek aerodynamics.

Which is just as it was in the very first A6 of 1994, a re-badged version of the sleekest executive car of the 1990s, the C4-era Audi 100. This is a much better selling point for the brand to aim at.

Thanks to a huge 30% improvement in refinement over the previous generation model, no other rival in the segment is quieter and as you can imagine, an awful lot of engineering effort's gone into achieving that result, including special acoustic glass and noise-absorbing foam rings in the tyres.

Even if you opt for the diesel version we tried, you'll struggle to hear the engine in front of you once underway.

You might be surprised that there's a diesel offered at all; rivals BMW no longer sell such a thing in this segment, but this A6 shamelessly continues to celebrate the black pump.

Indeed, Audi reserves arguably its most sophisticated engine tech for the TDI version, which uses the company's usual four cylinder 2.0-litre unit.

As with the Q5 and the A5 Avant, this means installation of the brand's 'MHEV plus' system, which offers a big step forward from Ingolstadt's previous mild hybrid technology.

For one thing, it uses a much bigger e-motor, providing 24PS and 230Nm of torque.

For another, it acts as more than just a starter generator, also able to drive the car on its own at parking speeds.

Plus, using a brake-by-wire set-up, the system can also regenerate energy at up to 25kW, so the compact lithium battery will always be topped up.

Another trait of the 'MHEV Plus' system is the way that it primarily slows the car using brake regen.

The friction brakes only kick in when the brake pedal is pressed harder. As we said, the 2.0 TDI unit in question is a familiar one - and the quattro 4WD system it must be paired with is familiar too.

Total output is 204PS, which is the same as the alternative four cylinder engine on offer, the 2.0 TFSI petrol, which uses the brand's usual 7-speed S tronic auto transmission.

Sadly here'll be no allroad SUV-themed version this time round.

Another disappointment is that the UK won't get the creamy-smooth 3.0 V6 TFSI petrol unit offered on the continent.

But we do get a PHEV e-Hybrid powertrain, which is based around the 2.0 TFSI four cylinder petrol unit, has quattro 4WD and offers 299PS and up to 63 miles of EV range from its 25.9kWh battery (20.7kWh of which is usable).

Across the A6 line-up Audi claims drive dynamics have been improved with this C9-era design.

To that end, there's a stiffer torsion bar, stiffer control arm bushings and increased front camber.

All of this is supposed to improve response from the more rigid variable-ratio Progressive steering rack and offer more road feedback, but the helm here still isn't especially feelsome.

A more fundamental aid to handling is the stiffer new 'PPC' or 'Premium Platform Combustion' chassis this sixth generation model sits upon.

This is by far the most dynamic-looking A6 Avant there's ever been.

With its lower roof line and pumped-up wheel arches, even an entry-level variant appears to have an S6-vibe.

Aerodynamics have been prioritised over practicality, resulting in a low drag coefficient of just 0.25Cd.

So it's just as well that the 4,990mm body length is a full 60mm longer than the previous C8-series model. The front end borrows cues from the A6 e-tron and the e-tron GT, with the familiar Audi rings moved from the enormous grille up to the bonnet and the headlights placed higher and wider across the new nose.

The sculpted rear has a striking light bar that sits below bright brake lights with OLED panels.

Wheel sizes are between 18 and 21-inches. Inside, Audi serves up most premium-feeling cabin in the segment, its architecture similar to recent models like the A6 e-tron, the Q6 e-tron and the Q5 (all developed at much the same time).

Which means a huge central fascia panel called the 'digital stage' that houses an 11.9-inch instrument screen and a 14.5-inch central infotainment monitor in a single curved housing.

There's no lower centre stack screen as in the old model, but customers can specify an optional 10.9-inch passenger side display. As long as you don't mind shiny black trimming, you should feel it to be all quite high-end, with high quality soft-touch finishes and leather-like materials wherever you look.

There are some nice tech touches, like the optional 'dynamic' sunroof which can be switched between translucent and clear - and also has an interim slatted 'pergola' mode.

We're pleased to see the retention of some proper physical controls around the dashboard too. Rear seat space is impressive; even a lanky passenger stuck behind a tall driver will have plenty of leg room.

And the swept-back roof line doesn't seem to compromise head space too much.

It has though, affected boot space, which once the kick-operated tailgate rises is revealed as 503-litres (down from 565-litres in the old car).

We should point out that the capacity figure we've just given applies only to the conventional TFSI petrol variant - which has a reasonable amount of space beneath the floor.

You don't get that with the diesel model, mild hybrid additions here reducing the capacity figure to 466-litres.

Predictably, it gets even worse if you go for the e-hybrid PHEV variant, which can only offer a mere 404-litres of space - less than a Honda Civic hatchback.

Activate the cargo sidewall catches and up to 1,534-litres of space becomes available with the TFSI variant.

It's 1,497-litres with the TDI.

And 1,423-litres with the e-hybrid.

Let's get to this A6 Avant model's pricing, pitched at the time of our test in Autumn 2025 from around £54,000 - just under £2,000 more than the equivalent A6 Saloon.

Both body shapes share the same familiar Audi trim levels - 'Sport', 'S line' (which is what most customers choose) or top 'Edition 1'.

Both body shapes also share the same choice of engines, so let's brief you on those.

As we told you in our 'Driving' section, the core part of the line-up is based around a couple of 204PS four cylinder 2.0-litre units.

The base unelectrified petrol TFSI powertrain is front-driven.

But the TDI diesel we tried is significantly different - in two ways; first, it has to be had with Audi's quattro 4WD system.

And second, it comes with Audi's latest MHEV mild hybrid set-up.

These key additions of course mean a substantial price premium, in this case £4,270 over the base TFSI petrol powerplant.

If you want to be able to plug your combustion A6 model in, then even more money's required.

To have the brand's 2.0 TFSI petrol unit embellished with Audi's e-hybrid Plug-in Hybrid powertrain (which comes with quattro 4WD built-in), then the price premium will be more like £10,000 over an ordinary petrol A6.

Which then takes you to around the £65,000 price starting point of the car that was originally supposed to replace this combustion-powered A6 estate - the all-electric A6 Avant e-tron.

But we'll assume that you're looking at this combustion-powered A6 Avant because, for whatever reason, you don't want an EV.

So what kind of value proposition are we talking about here compared to competitors? Well as a potential customer, your first thought when it comes to likely alternatives will probably be to compare this Audi with equivalent combustion models from the Ingolstadt maker's two arch-rivals in the premium part of this segment.

Only one of these, the Mercedes E-Class Estate, can be had with the same three-way choice of engine options as this Audi.

For reference, as we filmed, that more spacious Merc cost nearly £6,000 more than this A6 in base E200 petrol form, around £2,000 more as a diesel and around £4,000 more as a petrol PHEV.

Closer to the kind of executive estate this Ingolstadt model is trying to be is BMW's 5 Series Touring.

That can't be had as a diesel, but is comparably priced to this Audi in base 520i petrol form - and would save you around £1,700 as a PHEV.

The slippery shape of this C9-era A6 Avant suggests that it might be an efficiency class leader - but even with all the spangly new engine tech fitted it doesn't actually work out quite like that.

The TDI quattro mild hybrid variant records up to 54.2mpg on the combined cycle and up to 137g/km of CO2 and it seems like these official figures are close to achievable in everyday driving.

Obviously, you'll do a little worse than that with the alternative unelectrified TFSI petrol version - up to 39.5mpg and up to 162g/km. For a really frugal A6 Avant, you've to stretch to the e-hybrid petrol PHEV model which as we told you in our 'Driving' section can go up to 63 miles on the combined cycle using its 25.9kWh battery (20.7kWh of which is usable).

That facilitates a weighted combined fuel consumption figure of up to 123mpg and a weighted combined emissions figure of up to 52g/km.

The e-hybrid's maximum AC charging power is 11kW (well down on the 55kW a rival Mercedes E-Class PHEV offers); there's no DC charging option.

If the battery is completely empty, a full AC recharge to 100 percent takes around 2 and a half hours.

Brake energy recuperation performance has been significantly improved over the old-generation C8-era A6 TFSI e Plug-in Hybrid.

Now, the degree of recuperation intensity in electric driving mode (EV mode) can be adjusted to three different levels using paddles on the steering wheel and the A6 e-hybrid runs on electric power for as long as possible to fully utilise the available battery charge to the driver's destination.

This, even BMW and Mercedes would reluctantly have to admit, is a beautiful piece of engineering.

It always has been.

The A6 Avant was, after all, the first cars in its class to offer things like bonded-in flush glazing, a galvanised bodyshell, V6 TDI power, four wheel drive and advanced twin-clutch automatic gearboxes.

And in this improved smart-suited sixth generation C9-series guise, the cleverness continues, an extra dose of visual charisma blended with high technology and premium quality unsurpassed in this sector. This car's drawbacks, such as they are, don't appear to bother many potential buyers.

No it's still not the most spacious large executive estate in its class - but these days, it's large enough for that not to matter.

Yes, the extras can be expensive, but then that's the case with any premium executive car.

And it's true that the handling still isn't especially aimed at driving enthusiasts, though you can go a long way towards sharpening it by ticking the right options boxes.

This then, is a very complete product, perhaps a fitting sign-off for the combustion A6 Avant model line, if that's what this C9-era design is.

A thorough case, if ever there was one, of vorsprung durch technic.