Engine: 2.0-litre four-cylinder turbo-diesel
Transmission: six-speed manual
Power: 150 PS between 3,500 and 4,000 rpm
Torque: 320 Nm between 1,750 and 3,000 rpm
Fuel consumption (combined cycle): 68.9 mpg
CO2 emissions: 106 g/km
Top speed: 134 mph
Acceleration (0-62 mph): 8.6 seconds

Audi's third-generation A3 may not look much different from its predecessor but it's an important all-new model, the first to use the modular MQB architecture that will form the basis of several future small and medium-sized cars from Volkswagen group brands.

One big change is that the A3's body is a lot lighter than that of the previous model. Audi has made extensive use of aluminium and high-strength steels and, combined with savings in other areas, that makes the new car up to 80kg lighter than the old, despite being almost exactly the same size. Peugeot's recently-announced 208 achieves similar savings, suggesting that the big manufacturers have finally started to turn the tide after more than a decade in which cars got steadily bigger and heavier as customers demanded ever more in the way of creature comforts and safety features.

Touch and feel the new A3 and it immediately becomes apparent that Audi has also managed to edge things forward quite a bit in terms of one of its main traditional areas of strength - cabin trim quality. The choice of materials and finishes is excellent, and there are appealing new features such as fancier eyeball-style dashboard vents and a much slimmer pop-up screen for the optional MMI (multimedia interface) system. Several driver assistance systems are available as well, including active lane assist, traffic sign detection and parking assistance.

The A3's initial engine line-up has a familiar look to it, but as in the case of the new car's styling, that familiarity is somewhat deceptive, with carried over engine sizes and badges giving little clue to the incorporation of important weight-saving and other efficiency measures. To begin with, three engine options will be available, two petrol, and one diesel. The petrols, badged 1.4 TFSI and 1.8 TFSI, use direct injection and turbocharging to produce 122 and 180 PS respectively, while the diesel is a two-litre producing 150 PS. Audi claims an average fuel economy improvement of 12 per cent for these engines, which will be joined within a few months by a 1.6-litre diesel delivering 105 PS and a more powerful four-cylinder 140 PS 1.4 TFSI petrol. That features “Cylinder on Demand” (CoD) technology which deactivates two of the cylinders under light loads in the interests of fuel economy but at least to start off with, there's nothing quite as radical as Ford's innovative three-cylinder 1.0-litre petrol EcoBoost engine on offer.

Out on the road, the new engines for the most part feel quite similar to their outgoing counterparts, with the 1.4 and 1.8-litre TFSI engines and the two-litre diesel providing plenty of torque. Refinement levels are high. I also had the chance to drive the 1.4-litre fitted with CoD, and the cylinder deactivation process is barely perceptible, save for a discreet notification via the instrument panel when the engine is operating in two-cylinder mode. But if this A3's engines are thoroughly capable, it's in terms of its chassis behaviour that the new car really impresses - and that's important, because this is also the main area in which Audi is sometimes felt to suffer in comparison its rivals. Sport and S line models will normally have their suspensions lowered by 15mm and 25mm respectively, but buyers will, as a no-cost option, be able opt for the standard suspension settings instead, and all of the examples Audi made available for initial testing had this set-up. The new car's reduced weight immediately makes it feel more agile than the current generation of mid-sized Golf-based Volkswagen group models, but it's the new A3's superb ride comfort, at least on the standard settings, that really stands out. Bumps are smothered quietly and effectively in a way that normally only a much larger and heavier car could manage.

The initial range of three-door hatchbacks will be joined early on by a parallel line-up of five-door Sportback models, and, eventually, if past form is anything to go by, there will be a convertible version as well. For the first time, the A3 will also be available as a saloon, although whether there will be any takers for that in the UK, which traditionally shuns small booted cars, remains to be seen. Audi will begin taking orders for the new A3 later this month but the first UK cars won't be delivered until September. Prices start at a fairly keen £19,205 and the new range uses Audi's familiar SE, Sport and S line trim levels.

The new A3 is an excellent product but it will also face a much tougher competitive environment than its predecessors ever did. The new third-generation version of the Mercedes A-Class will abandon the controversial sandwich floor architecture and unusual tall look of its predecessors in favour of a handsome body with a much more conventional silhouette, allowing it to compete directly with the A3 for the first time. BMW's latest 1-Series is still fresh, while Alfa's Giulietta is the strongest model to be fielded by the Italian manufacturer for many years. Volvo is readying its new V40 five-door hatch, a replacement for its S40 saloon and V50 estate, and the switch to the more popular hatchback format alone should make the V40 a stronger competitor than the S40 and V50 ever were. Is the new A3 up to the challenge? I think it probably is.

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