Engine: 4.2-litre normally aspirated V8 petrol
Transmission: seven-speed S-Tronic automated manual
Power: 450PS at 8,250rpm
Torque: 430Nm between 4,000 and 6,000rpm
Fuel consumption (combined cycle): 26.4mpg
CO2 emissions: 249g/km
Top speed: artificially limited to 155mph, option to increase governed top speed to 174mph
Acceleration (0-62 mph): 4.7 seconds
Price: from £54,925

Audi's last RS 4, which bowed out back in 2008, was a glorious anomaly. When it appeared in 2006, Audi and its owner Volkswagen were pushing through big investments in diesels, economical small turbocharged petrol engines, and also in efficient self-shifting dual clutch DSG transmissions. The 2006 RS 4 didn't go along with any of that, though; under its bonnet it had a big, muscular, very revvy normally aspirated 4.2-litre V8 engine, which was paired with, of all things, a manual gearbox. Although it was packed with technology, it was, in concept, a surprisingly traditional package – notwithstanding the inevitable use of Audi's quattro on-road permanent all-wheel drive technology.

Now, a new RS 4 has arrived; it represents quite a big update but retains many of the characteristics of the old one. There's still a 4.2-litre petrol V8, and it still goes with the high revs approach, delivering 450PS at a staggering 8,250rpm. But Audi has worked hard on fuel consumption and CO2 emissions, which are improved by 27 per cent and 24 per cent respectively compared with the old car – although 26.4mpg and 249g/km are still figures that may put even some well heeled customers off. Power is up by 7 per cent, which means the RS 4 can get to 100km/h (62mph) in 4.7 seconds, compared with the 4.9 seconds its predecessor required. Top speed, as before, is governed to 155mph, although it is possible to increase this to 174mph.

The big mechanical change though, is the adoption of a seven-speed S tronic dual clutch gearbox in place of the old manual. S tronic is really just Audi's branding for the Volkswagen group's DSG transmission technology and at the time the previous RS 4 was introduced there simply wasn't a DSG gearbox that could handle the power of the high-revving V8. Now there is, and it appears in this car, although there's still four-wheel drive in the form of an updated quattro system.

One big change has nothing to do with the RS 4's engineering – the latest model is only available as an estate. The last RS 4 was built in saloon, estate and convertible versions, but with the estate-only policy Audi is returning to the roots of the RS line; the first RS car, the 1994 RS 2, based on the Audi 80, was only available in Avant (or estate) form. It's not just tradition, though that means the RS 4 is an estate – many of the buyers who previously would have gone for an RS 4 saloon are now buying the RS 5 coupé. Externally, the RS 4 differs just enough from the standard A4 on which it is based to stand out without being too vulgar. Blister-style extended wheel arches accommodate the RS 4's big tyres, which are mounted on thin-spoked alloy wheels that give everyone else a great view of the car's distinctive weight-saving “wave outline” brake discs – or its ceramic discs if you've paid extra for those.

Out on the road, the high-revving V8 engine is as exciting as the one in the old RS 4, whipping the car up to motorway speeds with ease – and sounding just about as good as any car can while it's doing it. Anyone tempted to mourn the loss of the manual gearbox will forget their sadness as soon as they sample the new RS 4's seven-speed S tronic transmission, which really does live up to the cliché about DSG combining the best advantages of manuals and automatics. Whether you choose to shift the gears manually with the paddles or just let the gearbox do all the work, changes are deliciously quick and smooth. The new car isn't, perhaps, quite as raw as the old one. It has something of a dual character; full of snarling purpose when pressing on, relaxed and refined the rest of the time – although there's an optional Sports Package costing £2,250 that includes a sports exhaust system for anyone who wants to hear more from the engine.

My guess is that any future RS 4 will bow to the inevitable tend towards smaller turbocharged engines, leaving old-school (in the best sense) V8s behind. That means this one will probably be a bit of a stand-out, sought out long into the future by enthusiasts who will prize its unusual combination of the traditional guilty pleasure of a big thrilling normally-aspirated petrol engine with all the safety and convenience of modern technology where the quattro four-wheel drive system and the rest of the car are concerned. That might actually make it rather a good investment – especially given that Audi like to keep things exclusive with the RS line, only producing the cars in smallish numbers relatively late in the underlying base car's life.

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