THE smallest four-door car in Audi's RS range might just be the pick of the bunch - for real-world driving, at any rate.

Of course, where the RS 3 is concerned, ‘small' certainly doesn't apply to the amount of power on offer.

The latest five-door RS 3 Sportback and its all-new Saloon sibling boast the world's most powerful production five-cylinder engine, churning out 400ps (and 480Nm of torque) from 2.5 litres.

That's some output for a compact car and propels it from 0-62mph in just 4.1 seconds.

You can hear it, too - high-performance five-cylinder engines have an off-beat music all their own, but Audi allow you to add even more drama to the soundtrack through the Drive Select system. Dial up the Dynamic mode and flaps in the exhaust system open up to add some earth-shaking bass notes.

The power reaches the road through a revised quattro transmission, with a seven-speed double-clutch gearbox for lightning quick changes.

Compared with the previous model, suspension components and traction control systems have also been upgraded - you can go even further and specify magnetic dampers and carbon ceramic brakes to stop this pocket rocket from entering orbit.

It'll also manage 34 mpg (Combined) if you can bear to leave it in Economy mode.

But get behind the wheel and you'll discover how Audi has pulled all the clever technical stuff together to create a car that's so much fun to drive, it's addictive.

Right away, a thin, leather and Alcantara-covered steering wheel gives you a connection with the road that feels quick and direct, almost like a classic sportscar. It's easy to forget there are electronics between your fingertips and the steering - it's that good.

Push the car through some demanding bends and it's light, nimble and quick. The four-wheel-drive keeps everything in order while you just enjoy the handling and the power.

It's nice to know it's faster than almost anything you're likely to meet on the road, but you don't feel the need to prove it - the RS 3 feels quick and agile at perfectly legal speeds.

Like any modern high-performance car from a premium brand, there is enough technology on board the RS 3 to send a spacecraft to Mars. But the truly brilliant trick Audi have pulled off is that you don't notice it.

Prices began at £44,725 for the RS 3 Sportback and £45,675 for the Saloon.