Audi RS3 2015 review

The five-cylinder powerplant in the hot Audi hatch started life as a Lamborghini V10. After you'd heard it once, you'll never forget it. The sound of a Lamborghini V10 sucking in prodigious volumes of air.

Floor the throttle and you can hear tiny actuators clear the airway to the V10 by opening the intake flaps in a millisecond.

At the other end of the car is an almighty bark followed by a crackle every time you change gears. It's one of the automotive world's most glorious sounds, generally savoured only by those who can afford a $500,000 Lamborghini. But now a very large dose of that experience has been fed into a very small car.

The Audi RS3 puts exactly half the Lamborghini's 5.0-litre V10 into what was originally a city runabout. It is so devilish it's genius.

The highly strung 2.5-litre five-cylinder engine under the bonnet came about because a boffin at Audi headquarters in Germany had the audacious idea to saw the V10 in half, almost literally, and squeeze it into a hatchback.

The new RS3's claimed 0-100km/h time of 4.3 seconds

This created — as incredible as it may sound — the world's second-fastest hot hatch. The new RS3's claimed 0-100km/h time of 4.3 seconds is 0.1 sec shy of the updated Mercedes-Benz A45 AMG due in December.

By virtue of going on sale here this week, for now the Audi is the fastest hot hatch on Australian roads.

Priced from $78,900 plus on-road costs it is by far the most expensive A3 sold locally. Audi likes to counter by saying it's the cheapest RS model it's had.

Appealing to the same buyers, the A45 AMG is currently listed at $75,800, although this is expected to creep up with the arrival of the revamped model.

The RS3 has slightly lower outputs (270kW/465Nm) than the coming A45 AMG (280kW/475Nm). Both all-wheel-drive and with fast-shifting seven-speed twin-clutch automatics, they are roughly the same weight.

But here's the thing: the RS3 feels faster, even without a back-to-back test. (Carsguide has done an opposite-hemispheres test, driving the A45 AMG in Germany a fortnight ago and the RS3 here last week.)

It may be the visceral sound effects of the RS3's engine and exhaust that give the impression of speed. Flooring the throttle in the Audi produces an enveloping sound — you can only hear an angry engine and tailpipe.

There's also the Audi's torque, which gives you a shove in the back a little sooner than in the Mercedes.

For now, I'll take a punt and say the RS3 feels as if it has more grunt in the real world, regardless of what's on paper.

The RS3 is frankly a missile, with technology that seemingly defies physics. A hatchback that's faster than most Porsches? That's no mean feat.

Its ride quality is another surprising highlight. Such big wheels wrapped in such low-profile rubber look at first glance like a recipe for back pain.

But the suspension has three modes — comfort, normal and sport — all of which are, well, comfortable.

Steering is precise and the RS3 feels balanced. It sits lower than other A3s, so there is less lean in corners.