Styling
The main upgrade of the performance is those lovely 22-inch Y-spoke alloy wheels. They're wrapped in Contintental SportContact 7 tyres measuring 285/30 all round, which are said to reduce high-speed understeer and promote better grip in both wet and dry conditions. Not only are the alloys lovely to look at, but they're finished in matte grey to complement all of the RS 6 performance's exterior detailing switching to the same colour, while the main badging (the four rings, plus the RS 6 logos in the grille and on the tailgate) is now rendered in black. The overall effect, especially when teamed against unusual yet appealing Tango Red paint, is to give the super-fast Audi estate even more visual clout than it had before. Which really is saying something.
Interior
As the standard C8 RS 6's cabin was a belter anyway, no drastic alterations are required for the performance's interior. The RS Design Package now comes as standard on the car, which means contrast stitching in red, grey or blue - the latter colour being a new choice - and a flat-bottomed, Alcantara-clad steering wheel thrown in for your troubles. Buyers also enjoy puddle lights which broadcast 'RS performance' onto the ground at night when you get into the car, while the 12.3-inch Virtual Cockpit instrument cluster has fresh graphics for its shift lights, mimicking those in motorsport as they go from green to yellow to red and then blinking when it's ideal time to shift up on the Audi's eight-speed Tiptronic gearbox if you're extending the car's mighty 4.0-litre engine (most likely, you'll see this feature only when you're on track).
Practicality
No major changes on practicality are brought about by the upgrade from the 600hp RS 6 Avant to this performance model, meaning you still get plenty of space in the rear for adults to sit comfortably, a decent-sized boot of 565 litres minimum, and the usual sensible Audi interior storage pockets and solutions. Ergonomically, too, the RS 6 performance is a winner, thanks to the triple-screen layout of its infotainment system keeping the climate controls on a separate panel - even if it's a haptic display, rather than physical buttons, it's still easier to use than burying the HVAC in the main central screen.
Performance
Audi fits larger turbos to the RS 6 performance, then ramps up the boost pressure from 2.4 to 2.6 bar for the 30hp and 50Nm gains in peak outputs. That means that this hefty old Avant can now run 0-62mph in 3.4 seconds, two-tenths quicker than it did with 600hp, and it automatically gets the increased top-speed limiter which is now set at 174mph.
Serious numbers for something which'll swallow the family and its dog, although you might be thinking it'd be hard to tell the difference between the non-performance version and this one, unless you'd got both back-to-back with some serious timing gear strapped to them. However, that's not the case: even when driven in isolation, there's no doubt the RS 6 performance feels even more rabid than it did before.
Perhaps helping here is the fact is that one of the changes you can't see is that Audi has removed a lot of sound-deadening in the car, which not only reduces its weight by 8kg but allows you to better hear the exhausts when you're driving the thing. Those grippier tyres are also said to help sharpen the throttle response, further accentuating the RS 6's speed.
All told, it adds up to a deeply impressive vehicle. Weighing in at almost 2.1 tonnes, you never, ever feel like the RS 6 performance is a great, big heavy car. This applies when slowing it down as much as getting it going, although you can upgrade from the regular performance model to one equipped with carbon-ceramic discs if you need more braking power - trust us, you really don't.
And the sheer pace of the thing has to be experienced to be believed. You treat the throttle pedal in the RS 6 performance with a good dollop of circumspection, because even on quarter or half openings, the immense midrange clout of the biturbo V8 up front is enough to have you soon in the realm of illegal speeds on the public roads with very little delay in the build-up. Open the taps fully and the furious explosion of noise and acceleration that the RS 6 serves up is utterly intoxicating, albeit pretty much inaccessible in any gear higher than second. Quick, then? Oh yes. With that proverbial capital 'F'.
Ride & Handling
Perhaps the even better news about the Audi RS 6 Avant performance is not just that it has got faster in a straight line, it's also finer and more rewarding to steer when you've got to thread it through some bends, too. Accepting that it's a physically large car and is therefore never going to be the most delicate vehicle in the world when it comes to handling, there's nevertheless a huge degree of fluency, adjustability and downright enjoyment to hustling the RS 6 along.
Chief among its weaponry is the standard-fit RS Dynamic Package, which not only brings in the raise in the ultimate limited top speed, but also dynamic all-wheel steering and the quattro sport differential on the rear axle. This goes with the self-locking centre diff of the RS 6's quattro set-up, which basically favours a 40:60 front-to-rear torque split, with a maximum of up to 85 per cent able to be channelled to the back of the car.
The C8 RS 6 was already a mesmerising thing for handling, but these changes have sharpened the performance model up and made it even more rewarding. The steering deserves high praise, as it's one of Audi Sport's best and most feelsome systems, while the body control is as near to absolute as makes no difference. In finest fast-Audi-quattro fashion, the RS 6 can therefore demolish any road you show it with equal aplomb, whether it's a narrower, more technical route or something featuring higher-speed, open and well-sighted corners. And that counts no matter the weather outside, as well.
Yet it's still, underneath all of the bulky RS clothing, an A6 Avant (of sorts), so when you're not testing out whether the performance feels sharper than the old 600hp model, you'll revel in the refinement levels. Despite those colossal 22s at all corners, the Audi's adjustable damping does a good job of slackening everything off to just the right degree for ride comfort, which allows the RS 6 performance to excel at both motorway work and A-roads cruising with ease. Around town and on the poorest surfaces, yes, you are aware that there are big alloys hanging unsprung and that you're in something that's very performance-oriented, but overall the 630hp Avant is perfectly fine to live with as a daily driver.
Value
The price of the Audi RS 6 has kind of crept up 20 grand in four years, if you look at it one way. Where a 600hp model was available from just shy of £95,000 in 2020, now you're looking at spending at least £115,480 to get into any version of the performance. It has also, here in the UK, completely replaced the old 600hp car (whereas the 'base' V8 is still available in the vehicle's German homeland, for instance), but of course you're getting all that extra power and all that extra, um... performance from it for the additional outlay.
Equipment levels are generous as standard, with every 630hp version also gaining the Bang & Olufsen 3D Premium Sound System, Park Assist Pack with Park Assist Plus, a head-up display, 360-degree cameras and those 22s from the off. Like any self-respecting Audi RS, you can go further with the Carbon Black and Carbon Vorsprung models, which only really add styling gewgaws and a few weird tech oddities (like Night Vision) to the party if you want them, but ticking those trim grades for the RS 6 performance will simply push its price ever higher.
That said, there isn't really a clear, obvious rival for the Audi at the moment - save for faster versions of the soon-to-be-replaced
Porsche Panamera Sport Turismo - so how you view an asking price of £115,000-plus for a car as (undeniably) broadly talented as this one will have to be taken in the context of it being something of a Hobson's choice.
Verdict
Rapid, comfortable, poised, refined, practical, desirable, technologically advanced and, most impressively of all, a proper riot to drive, the Audi RS 6 Avant performance is an absolutely blinding vehicle. You'll need to pay a lot of money to own one and have pockets as deep as the Mariana Trench to keep its rapacious V8 in fuel, but if you can tick those two boxes then the RS 6 performance goes down as one of the most gratifying, ultra-talented machines that Audi has ever committed to production. Or, indeed, any manufacturer, come to think of it.
