Move over Mazda RX-8, sayanora Nissan 350Z: Britain’s favourite premium coupé, the Audi TT, is reborn.

Audi will take the fight to the new pretenders by widening the MkII TT range. A third bodystyle, the first S and RS high performance TTs, and diesel power are all waiting in the wings.

It all kicks off in the UK this October, when dealers hand over the first coupés. Two models will be available at launch: a turbocharged 2.0-litre costing £24,625 and a £29,285 3.2-litre V6, with quattro four-wheel drive.

Re-inventing an icon is no easy task, but Audi’s design team has retained the iconic shape while adding more muscular surfaces and eye-catching details. It’s a TT, but grown up.

The headline news is that this TT is a serious sports car, vows Audi, rather than a tarted up Golf.

Want proof? While the new Golf is mostly steel, the TT gets a bespoke structure, which is nearly 70% aluminium. So the 2+2-seat coupé achieves the Holy Grail: it’s bigger but lighter, faster yet more frugal. And it’s stiffer, too, so expect sharper handling and improved refinement. If the TT steers and rides as well as the sporty Golfs, it will live up to Audi’s billing.

Transmission is via six-speed manual gearboxes, or the double clutch transmission, now branded S-tronic by Audi. That’s not the only change: one Audi source let slip that the ’box will have seven cogs, just like Bugatti’s Veyron.

What else is in the pipeline? The two-seat roadster, with its rag top roof, will make its debut this autumn, with sales in spring 2007. Although the official line is “no comment” on the Shooting Brake, the sleek wagon (already unveiled in concept form) follows later that year and Audi may make the Shooting Brake the entry-level TT model.

And a diesel? “If we win the Le Mans 24-hour race, then we will think about a diesel,” said Audi engineering boss Ulrich Hackenberg. “Winning would prove a diesel is a sporty engine.”

A new 225bhp V6 diesel has been penciled in for the TT, and a 170bhp 2.0-litre TDi can’t be ruled out either.

Whispers suggest two flagship versions. Audi is experimenting with a high pressure turbo version of the 2.0-litre petrol four, which could take power beyond 300bhp. The RS should go even further. If it gets the green light, the TT-RS should run a bored-out version of the V6, extended to 3.6-litres. With a turbocharger, the V6 should kick out 350bhp. That should end any snide comments about the TT’s sporty abilities, once and for all.