Nissan marked its recent revival, with first-half profits of more than £1bn, by exhibiting two concept sportscars at the Tokyo show.

Carlos Ghosn, Nissan president, claimed the 350Z sports coupe and GTR, a surprise unveiling, signalled a "viable and distinctive brand" that was en route "from revival to renewal".

Mr Ghosn believed it was important for Nissan to display a range of concept cars with its existing models. Strong products, he said, would solve any problem faced by a carmaker.

The 3.5-litre V6 350Z sports coupe, to be called Fairlady if sold in the UK, will be priced keenly at £20,000 in the US, to undercut Porsche's Boxster. It marks the return of the company's iconic Z-car range.

Patrick Pelata, Nissan executive vice president in charge of the 350Z, warned that the model might not be a viable proposition for European markets.

He said: "To be as good as a Boxster or Mercedes SLK you need excellent dynamics in Europe - the most difficult market in the world. Japanese and US specifications do not provide that because no-one in these markets drives at 125mph."

Nissan would need to invest in reducing high speed wind noise and meeting safety regulations. Additional obstacles included 10% import tax, "painful" large engine tax penalties and low sales volumes.

If the profitability issues can be resolved Mr Pelata expects the 350Z to enhance Nissan's image in Europe.

Nissan also debuted the GTR concept, minus engine or transmission, at Tokyo. The GTR will be pitched against the Porsche 911, with a 400bhp V8 rumoured for a 2003 launch. Electronically controlled 4x4 is a likely feature.