The recently introduced model of Audi, which also features in the latest Bollywood movie "Race 2", costs around Rs.1.80 crore and is among the premium products of the German car manufacturer available in India.
According to police and fire brigade, the cause of the fire was not clear and it was extinguished shortly after it started.
Though there were no casualties in the incident, the northern land side of the sea link was jammed for nearly two hours before traffic was permitted to cross the bridge.
Audi India head Michael Perschke told media-persons that preliminary investigations revealed that some modifications may have been carried out in the vehicle, but on an investigation would reveal more details.
The incident happened during the prestigious two-day Fifth Mumbai Parx Supercar Show-2013 in which over a hundred of the most expensive cars used by top Mumbaikars took part.
Among the participating cars were the country's only Lamborghini Aventador Roadster, costing nearly Rs.5 crore, and Ferrari 458GT.
Also present was liquor tycoon Vijay Mallya's customized golden Lamborghini Aventador, several other Lamborghini Aventadors, Ferraris, BMWs, Audis, and Mercedes-Benzs.
It was not immediately clear whether the destroyed Audi R8 was also taking part in the car show at the time of the incident.
The Parx Supercar Show is organised by the exclusive Super Car Club jointly founded by industrialist Gautam Singhania and Autocar India editor Hormazd Sorabjee.