Although rear leg room isn't the most generous in the RS4 if taller occupants sit up front. Equipment levels are as you'd expect from a car of this price bracket. Riding on unique alloy wheels framing huge disc brakes, and fronted by the latest Audi single frame grille, the RS4 gets black metallic Valcona leather-upholstered RS bucket seats, cruise control, front seat heating, a BOSE sound system, front and rear acoustic parking sensors and electronic tyre pressure monitoring. Anti-lock brakes with electronic brake force distribution, Bosch's latest ESP v0.8 stability control system and no fewer than eight airbags also feature as standard.
The Avant's load bay is stuffed with smart ideas, Audi's designers having a field day with ways to boost the diminutive Avant's practicality. There's a split/fold rear seat that accesses 1,184 litres of capacity. The floor of the loading bay is split laterally, with a 65-litre cubby providing additional storage space. Chrome lashing eyes, stowage nets and a heavy-duty reversible mat also feature.
The RS4 Cabriolet features an electro-hydraulic soft top rather than a heavy and complex folding hard top arrangement. It lowers at the press of a button in 21 seconds and can be operated at speeds of up to 30km/h, ideal for when you're nosing through traffic and the heavens open or when you've just spotted a parking space and need to make a rapid exit. The hood features an acoustic liner to keep the interior quiet when it is in position and a glass rear window ensures decent rear visibility.
The RS4 has proven a very durable performance car but it does have a few items you'll need to look out for. Check for vibration under braking as the Audi has a record of warping front brake discs under severe use. Many RS4s have fairly creaky front suspension as well, although many owners just accept this with no ill effects. Check the tyres for wear as these will be costly, but the 4wd system means that the RS4 tends to be less demanding on rear tyres than, say, a BMW M3. Take a good look at the alloy wheels as well as kerbing damage can lead to the finish flaking quite badly. Otherwise, the impeccably screwed together RS4 should be a less temperamental partner than any other 170mph vehicle you can imagine.
(approx based on a 2006 RS4) A clutch assembly kit will be around £275, an alternator should be close to £200 and a radiator around £180. A set of front brake pads and discs will run you around £900 and a starter motor close to £165. The first service at 15,000 miles will entail an oil change and costs can be kept down if you provide oil, either Fuchs Titan or Castrol Edge seem to be the lubricants of choice amongst RS4 owners.
The rather unsubtle turbocharging was ditched with this generation RS4, replaced by a naturally aspirated engine that revs to 8,250rpm and generates a monstrous 414bhp. A re-engineered four-wheel drive system deploys that power better than ever and more is routinely directed to the rear wheels, which excises the stodgy understeer from the quattro drivetrain. Lower, wider and utilising aluminium body panels to keep weight down, this RS4 gave BMW and Mercedes something very serious to think about.
The engine is a fascinating piece of technology. The RS4 was the first Audi to feature the 'high-speed engine principle' which means that rather than concentrating on low-down slugging power, the engine has the sort of wail more reminiscent of a competition car in the upper reaches of the rev range. Fully 90 per cent of the car's maximum 430Nm torque figure is available at any point between 2,250 and 7,600rpm.
The end result is a car that will accelerate through 60mph in 4.6 seconds and on to 125mph in just 16.6s. A gentle electronic limiter draws a close on this headlong rush at 155mph. The gearing and power suggests that without this limiter, 180mph would be fairly easily achievable. The lack of a turbocharger means that there isn't the same savage punch the old RS4 could generate at very low revs, but the mid-range and top-end urge of the RS4 means that on the open road and track it is quite simply in a different league. To get some idea of the thrust available, consider the fact that at 251bhp per tonne, the RS4 contrived to make BMW's E46 M3, with 215bhp per tone, seem rather underpowered.
Where BMW has traditionally had Audi's measure is when it comes to the sort of handling subtlety valued by those who really know cars. Communication, adjustability, directness and linearity of response have all been areas where Audi have often been a notch off the best in class but the Ingolstadt company has made great strides which change that with the latest RS4. It's still not as lairy or entertaining as an M3 but it is undeniably effective and hugely charismatic.
The Audi RS4, especially in its sleeper Avant estate guise, comes as close to the template of the ultimate all round performance car as anything we can think of. It's brutally quick, refreshingly practical, impeccably built and deeply gorgeous both inside and out. Audi cracked it with this one. It consigns the original Quattro coupe to the history books.