##aud4q.jpg --Right##VW Group's platform-sharing machine may have made it almost impossible to differentiate models in the stable, but it has allowed sub-brands to pinch an engine here or a chassis there in the quest for ultimate driving satisfaction. Take the new Audi A4 1.8T quattro Sport for instance.

Using the same 1.8-litre five-valve-per-cylinder turbocharged engine as the Audi TT and the SEAT Leon 20V T Sport matched to Audi's four-wheel drive system, the quattro Sport claims to offer the traction qualities of the A4 quattro but with more power and economy than the six-cylinder derivatives in the range.

But unlike a Lexus IS200 or an Alfa Romeo 156, there are precious few visual clues to suggest this is any different from an entry-level 1.6 SE: 16in ten-spoke alloys, twin chrome exhausts, lowered suspension and a discreet red 'T' on the bootlid complete the look. But the performance figures are something lesser A4s cannot offer. With a 0-62mph time of 7.6secs (1.8T Sport: 8.4secs) and a top speed of 145mph (1.8T Sport: 138mph) the tiny T on the bootlid is the view most other drivers are going to get of the newcomer.

At an average of 31.7mpg, economy is respectable, especially when it's only 4mpg shy of the 1.8T Sport's. On the road, a torque boost of 18lb-ft to 173lb-ft provides greater urgency through the gears against the 1.8T Sport and the lazier appetite of the 2.4 V6, but with its wider torque spread between 2,000-4,600rpm and close-ratio six-speed gearbox, quick progress is guaranteed.

With all four wheels driving, the quattro Sport rarely comes unstuck through the corners, but there's a downside to this frenzied four-pot. Even in sixth gear, at the legal limit on the motorway, the engine is spinning at a buzzy 3,200rpm, which means a long haul can become a noisy affair. The ride too, is fairly firm.

No such gripes inside, though. Recaro half-leather sports seats with electric lumbar control and a leather-clad height and reach-adjustable steering wheel help to provide a peerless driving position - add in brushed aluminium door and facia inserts and white-faced instrument dials (backlit with red numbers which look fantastic at night) and there are few cars that can match the Sport's cabin. Other standard-fit items include climate control, traction control, ABS, all-round electric windows, driver, passenger and side airbags plus a three- year/60,000-mile warranty.

Whether fleets will sign up probably comes down to the price. At £27,150 on-the-road for the 1.8 T quattro Sport , this makes the BMW 323i SE at £24,895 look cheap - which is nothing compared to the Saab 9-3 2.0T SE 5dr at £24,645, Volvo S40 T4 SE at £23,365 and the Alfa Romeo 156 2.5 V6 Veloce at £20,685