It was only announced last week, but Auto Express has already got behind the wheel of the car Audi hopes will hit its rivals for six. This is the new TT V6 - and it promises to deliver the performance and refinement fans of the futuristically styled coupé have been craving since its launch.

But it's not only the engine that has changed. The car features a revolutionary new Dynamic Shift Gearbox (DSG), which uses two clutches to allow drivers to pre-select the next ratio automatically. It also has a few styling tweaks to distinguish it from lesser models.

In the metal, the car looks little different. Audi has sensibly left the lines well alone, but added a few extras to make the fastest TT appear a bit more aggressive. A mesh grille, 18-inch alloys, deeper air intakes, fat twin exhaust pipes and a beefier rear spoiler are the visual clues that this is anything other than a normal version.

Fire it up, though, and there's no mistaking the engine note for the standard car's four-pot. The 240bhp 3.2-litre V6 - shared with VW's Golf R32 - might only have 15bhp more than the fastest 1.8 turbo, but if it's aural pleasure you're after, the car emits a wonderfully throaty burble at idle. Open it up and the motor growls, like only a V-shaped block can. So in the style and seduction stakes, the TT V6 scores highly. But how do the new engine and transmission measure up where it matters - on the road?

In fully automatic guise, the TT drives like any other auto coupé, with a choice of economy or sports modes and a relaxing nature round town. But the trickery of the transmission is evident when you press on - keep your foot to the floor and the gearbox changes seamlessly, with no lull between shifts. And thanks to a computer chip that senses your driving style, the car is always ready to shift up or down - kickdown is instant if you plant your right foot, while gentle braking will persuade the unit to step down a ratio.

So far so good, but Audi says keen drivers will use the sequential manual mode - and that's where the transmission comes into its own. As there are two clutches, drive is never taken away from the wheels, as would be the case with a normal manual or auto. Instead, as you shift gear, the second clutch moves to the next ratio, up or down depending on the car's speed. When you're ready to change cogs, just snick the lever back or forward, or use the steering wheel-mounted paddles, and the next ratio is engaged instantly.

And it works brilliantly. DSG takes milliseconds to shift up or down, with incredible in-gear acceleration as a result. The TT is quick off the mark, too. A Formula One-style 'launch control' system determines the optimum engine revs and clutch position, propelling the car from 0-60mph in only six seconds.

That said, some drivers will still prefer the more natural control of a manual box and clutch pedal, and it's a shame Audi won't release a cheaper version with the six-speed unit offered in the Golf R32. Otherwise, the V6 is a fine car. It's sportier than four-cylinder models, while the extra weight of the engine makes the rear end feel lighter and more alive, without affecting grip.

What remains to be seen is if it'll catch on - it's an impressive technology showcase, but will anyone pay nearly £5,000 more than a 1.8 T 225 Coupé for a car with little performance benefit?