On the rare occasions that you can find a straight long enough to exercise every last one of this Audi's 414 horses, you'll hear the most compelling sound. It doesn't come until the engine is spinning hard, but then you hear an extraordinary velvet thump as eight cylinders beat out a high-pressure, low-note rhythm that's nothing short of electrifying.
But your exhilaration will be short-lived as you have to deal with the considerable velocity that you have accumulated.
This car is warpingly fast - very nearly as rapid, in fact, as a £121,750 Ferrari F430, which it trails by a mere tenth of a second to 62 mph. From a standing start, you can be doing 100 mph in just 10.5 seconds. All of which raises the question of what the point of it all is. The answer is not much, bar those fleeting seconds of intense entertainment. But it has always been that way with high-performance cars. Part of the pleasure lies in anticipating those flat-out moments, even though most of your time is spent toddling along, using only a fraction of the firepower.
There's more to it than this, of course - which is just as well, given the RS4's price. The least you can pay for an example of the compact A4 saloon on which it's based is just over £19,000, which buys you a nicely built but sparsely equipped 1.6 litre saloon of four cylinders, 101 bhp and front-wheel drive. Pay another £31,000 and you have the ultimate version of the car, the RS4, which, though it looks fundamentally the same, is of shockingly different character. You get twice as many cylinders, four times as much horsepower and a heap of extras, much of it aimed at ensuring that this car is as secure as it is speedy. Four-wheel drive ensures that the huge tyres can handle the power whatever the weather, the brakes are big and beefy, and if you opt for the sports seats you'll feel like you're clamped in - just what you'll need to explore this car's extraordinary reserves of grip.
This all sounds rather brutal and wearing, yet it's a remarkably civilised vehicle. Driven briskly rather than all-out, it's remarkably serene. The engine is muted and the suspension absorbent, especially for a sporting Audi.
Best of all, though, is the way its abilities meld to provide a deeply satisfying sporting drive. It's a bit like wearing a decent pair of skis, or wielding a finely tuned racket. The driver's pleasure stems as much from the meaty feel of pedals and gearshift, the weight and precision of the steering and the car's deft way with corners as it does from the explosive potential of its performance.
It all adds up to a harmonious confection, in contrast to almost every previous sporting Audi, whose disappointments have betrayed their clean, contemporary styling and their build quality. It's not cheap, this RS4, but in the world of performance cars it is strikingly good value.
Price £49,980 (Audi RS4)
Max power 414 bhp
Max torque 317 lb ft
Max speed 163 mph
0-62 mph 4.5 sec
Fuel consumption 19.3 mpg
CO2 emissions 324 g/km
BMW M3 £44,275
The car Audi set out to beat and, mostly, has. Defter on twisty roads,
less of an all-rounder.
Mercedes C55 AMG £49,740
Not as quick, nor as accomplished, yet costs similar money. Less