What is it?
The Audi RS6 Performance is a bit questionable, if we're honest. After all, taking the existing standard, 552bhp Audi RS6 and adding another 45bhp feels a bit like throwing a sparkler onto an enormous bonfire. Things were already really very hot anyway, so it seems unlikely that the gesture is going to bring much more to the party.
Still, the RS6 has always been a brutish but compelling thing, with its raucous twin-turbo V8 delivering visceral, nonchalantly ridiculous straight-line performance and a wonderfully soft-edged yet aggressive V8 soundtrack. This Performance version costs a further £7000 on top of the £79,505 asked for the standard RS6, but for that extra outlay you get not only the extra power - which drops the 0-62mph time by 0.1sec - but also an overboost function that sees torque rise to 553lb ft, along with 21in alloys, a sports exhaust and a 'Titanium' styling pack that brings contrasting front splitter, door mirrors, rear diffuser and Quattro badging on the front grille.
What's it like?
It's still a battering ram of a car that seems to bull its way through corners in a manner that, honestly, doesn't sit particularly well on UK roads. Our test car came with optional £1000 Sports Suspension, which brings adaptive steel springs instead of standard air suspension. Even with that and a lot of trail braking to keep the weight where you want it, the RS6 Performance is prone to understeer, and the quite numb, heavy steering also does little to hide the fact that this is a fairly unwieldy car.
That's not to say that it's terrible to drive. We favour the lighter normal steering mode over the artificially heavy Dynamic mode, and the RS6 scythes through broad, sweeping curves in a satisfyingly fluid, meticulously neutral fashion. But there's little or no finesse to the way it goes about anything more complex or demanding than that; a Jaguar XJR or the outgoing Mercedes E63 AMG both have more subtlety and poise to their handlin, which makes them feel more engaging and responsive.
That's not our only gripe. Again, on the optional suspension, ride comfort in Dynamic mode is pretty woeful, with wince-inducing short-sprung vertical damper movements that never let the car or passengers rest. At least in the softer modes it calms down a bit, and the trade you make in more noticeable body roll is an easy one to take in favour of the more forgiving bump absorption and generally more settled ride comfort, although this always feels like a firm car that's working hard to keep a lot of weight in check.
Now to what the RS6 does well: speed. And lots of it. Good grief, the RS6 is ludicrous. Can you feel the difference between the Performance and the standard car? It's been a while since we unleashed a standard RS6 in the UK, but honestly you'd struggle to tell. The extra mid-range grunt is always going to be more telling than the outright top-end performance, so maybe there's a fraction more ballistic response when you're riding the overboost function, but the over-indulgence of pace is there to scramble your insides in either version of the RS6. There's no launch function, so just standing on the throttle is all it takes to experience the full madness of a car of this size stropping up to 62mph from rest in 3.7sec. The four-wheel drive system means you get virtually no slip away from the line even in poor conditions, and from there on you can enjoy the impressively flexible, stupidly potent power delivery offered by this rather joyous twin-turbo V8. It sounds great and it is brilliant fun to use in all sorts of situations, helped by the smooth-shifting eight-speed Tiptronic automatic gearbox.