The Avant part is particularly relevant, because this time the RS4 will only be available in estate format, Audi having decided that the RS5 coupe and convertible cover the other body-style bases - and not wishing to cannibalise sales from its own model range. There's also a hell of a lot of stuff going on with this car, so bear with me here. First up, the styling is the relatively simple bit, and more of the same kind of reserved-but-tough appearance that RSs are famous for. So you get a new Bauhaus-stark single-frame front grille, the clean squint of the recently face-lifted A4 headlights and a deep front bumper punctured by hefty inlets. There are the usual blistered squircle arches and deeper sideskirts, and the rear gets a diffused back bumper and the traditional oval RS tailpipes either side. It sits 20mm lower than the A4 over standard 19-inch ten-spoke forged-aluminium wheels, and the hefty 265/35 section tyres mean that a decent stance comes as standard.
It looks like an angry robot: subtle enough to slip through unnoticed, aggressive enough to be obvious to those who know. Which is good. Underneath - as you'd expect - is a whole heap of quattro, with various mechanical modifications to make it more fun to drive. So you get a basic front-to-back torque split of 40/60, with the potential for 85 per cent of the available shove to be directed to the rear wheels, or up to 70 per cent to the front. The sport differential also allows for active torque vectoring, meaning that it can fiddle torque to the wheel with the most grip depending on the situation, and also siphon off a little power to an outside diagonal wheel to quell understeer if needs be.
There's also an optional DRC (Dynamic Ride Control) system as per the RS5, which uses diagonally opposed pairs of shocks linked by hydraulic lines and a central valve, meaning that the car can level out more efficiently under load by keeping extra control of the front outside wheel when you're really going for it. However, it has to be said, the standard suspension set-up is pretty sorted.
Also standard are funny-looking ‘wave' brake discs, a bit like those on a lot of sports bikes. They resemble cookie-cutters, are internally ventilated for heat sink duties, offer similar stopping performance to a standard steel disc but save about three kilos of unsprung mass, thanks to the missing bits. Full carbon-ceramics are an option if you're feeling properly committed, and save even more weight, though they're probably not needed unless your commute includes the Nordschleife or Stelvio Pass.
So far, so RS standard recipe. But now comes the interesting bit. Up front is a naturally aspirated, FSI direct-injected 4.2-litre petrol V8 that produces 444bhp at 8,250rpm, a red line at 8,500rpm, and with maximum torque of 317lb ft available from 4,000 to 6,000rpm. Basically, the same engine as the RS5, plus a few tweaks, it drives through the only transmission option: Audi's 7spd S tronic dual-clutch 'box. Which is interesting. An estate car with a super-high-revving V8 and slick-quick DSG? Sounds like a TG kind of car.
Which makes it a bit of a surprise when you first drive it and think: "This is very... nice." Essentially, the RS4 feels quite firm when pottering - even in Comfort mode - but the 'box slips between ratios without a murmur, the engine mumbles away happily and you could be forgiven for thinking you're in a more humble S line variant. The V8 whuffs a little on start-up, but with the standard exhaust (there's a louder optional sports exhaust), there's not really that much to give away the potential. Even the interior - brilliant ‘batwing' sports seats aside - is pretty much high-end Audi standard.
It's not until you really get going that the RS4 starts to make an impression. It was streaming wet when we tested the car on some rather lovely mountain roads in Austria, and there couldn't have been a better test. With mid-corner standing water, bumps and surprisingly scary cliff drops, the quattro really earned its money. And the most appropriate compliment is that it feels fairly natural for such a complex arrangement of systems. Grip is phenomenal - especially in long, loaded-up corners - with the kind of burly, slightly understeer-prone attitude that gives lots of confidence in the wet. Poke in a bit more throttle smoothly, and you can even make the whole thing oversteer (there's a self-locking crown-gear centre diff that helps with the feeling), though it's not rear-wheel drive and never really feels like it. Not that it should - the confidence and surety is one of the reasons you'd buy an RS4.
Where you'd be happily chattering the traction control light in something like a C63 AMG, or indeed slewing around like a rally driver, the RS4 simply grips and goes, or understeers gently away from the apex. Be a little bit more brutal with the transition from the straight ahead, and if it's slippery enough, the RS4 will be a bit more spectacular, though it's not as happy as when you're being neat and tidy. The 'box is quick and confident, and changes with the kind of technological efficacy that makes a manual look a bit agricultural, huffing out the most delicious downchange blips this side of a Ferrari as it does so. It also manages to disguise proper speed in a veneer of control so precise that you'd probably only get a real sense of just how fast it can be by following an RS4 in something else. It's properly quick and exceptionally confident.
But there's a slight fly in the ointment - you absolutely have to cane seven bells out of the engine to make the most of the chassis. Now, in most cases, a vocal V8 smashing its way repeatedly off a 8.5k limiter would be a thing of beauty, and it's addictive to use, even if just for the glorious noise. But, on this brief acquaintance, it just feels like one step too far for an estate. There's a niggling feeling that the RS4 could do with a torquier, brawnier engine rather than a screamer. It's not slow by any means, but you constantly need a gear or two lower than you think. And then you start to consider the thumping bi-turbo 6cyl diesel engine that Audi also makes, and all sorts of RS-type heresy starts to invade your thoughts.
It does, however, come with a decent spec and a reasonable price tag for the performance bracket, mainly because with such inherent practicality an RS4 could definitely be your only car. Once you've added the Sport Package that includes DRC and dynamic steering (alters steering weight and even counter steers in some situations), the black-tipped sports exhaust (crucial) and bigger 20-inch rotor wheels - all for £2,250 (a saving of just under three grand if you specced the kit individually). There's not a lot more you'd need.
