Audi's Le Mans-inspired road car project is progressing into the design stage, although it has yet to be signed off for production.

Speaking to Autocar at the Shanghai motor show, Audi technical chief Wolfgang Durheimer said there had been "no business decision on series production, but we hope to create one".

A platform for the model has also yet to be finalised, and the engine remains an "open question". To closely link the Le Mans race project to the road car the model would need to be a diesel-electric hybrid, but diesel lacks global appeal, particularly in key markets China and North America.

But new rules set to come into Le Mans in 2014 could swing the favour back towards petrol models, which could in turn make an easier business case for the Le Mans-inspired road car.

Durheimer also said there was space below the R8 for an Audi sports car, as well as above it.

He said a Porsche Boxster-sized model had been in "design, packaging and evaluation" phases, but the project was not a priority. "It's difficult to realise for production," said Durheimer. "We would want to bring technology to the segment, but getting the volume and pricing right for a mainstream sports car would be a challenge."

"Something mid-engined would be the perfect solution for an Audi of this size," he added. "It would have two boots, perfect weight distribution and perfect handling."