Audi is about to unveil one of the most powerful TT ever. Set to compete with models like Porsche Cayman S and BMW M3, the new TT RS will take styling cues from the TT Clubsport concept, that was unveiled earlier this year. The new model is to be unveiled sometime in 2009.

The TT RS will be powered by a turbocharged version of a 2.5-litre five-cylinder petrol engine that will deliver around 350bhp, or an output of 140bhp per litre.

According to an insider who has heard the TT RS, Audi's hot new coupe makes "a fantastic noise, just like the original Quattro".

Power might be 50bhp down on the 400bhp BMW M3, but the TT RS will make up the deficiency with a lighter kerb weight, with the potential for a power-to-weight ratio of around 250bhp per tonne, and a whole heap of turbocharged torque.

It's likely that the 350bhp TT RS would only be offered as a coupe, as the inherent strength of a car with a roof would be necessary to deal with the forces generated during cornering, acceleration and braking.

Also Audi is working on a second version of the TT, called "S". This version will be powered by a turbocharged four-cylinder engine with an output of 261 hp. It will be released in 2008.