features depicted in the concept car would find their way in future Audi production vehicles. The car was production-ready and garnered a lot of acclaim from both the motoring press and prospective buyers but due to the economic downturn of the 1990s, Audi decided not to press ahead with the project as the demand would not outweigh the development costs for the model. The concept car was unveiled at the 1991 Frankfurt Motor Show. Audi quattro concept (2010) At the Paris Motor Show in 2010, Audi presented the quattro concept on the occasion of the 30th anniversary of the original Audi Quattro and the Audi quattro four-wheel-drive system. Based on the RS5, it features a modified 2.5 L five-cylinder TFSI engine shared with the TT and a 6-speed manual transmission from the S4. The engine was claimed to generate a maximum power output of and of torque. The revolutionary design features depicted on the concept car would eventually make their way on future Audi models. The concept utilised aluminium and carbon fibre construction which helped to achieve a total dry weight of . Weight saving was kept in consideration even throughout the interior and the seats also weighed each besides having adjustment motors. The dashboard featured an LCD console displaying vital information about the car and buttons arranged in a vertical way on the binnacle harked back to the original Audi Quattro. The wheelbase was shortened by and the roof line was shortened by as compared to the RS5. The Quattro four-wheel-drive system used in the concept was a rear-biased design utilising a two-stage differential distributing power front and aft through planetary gears. The concept utilised carbon-ceramic braking system for improved stopping power. The car had a claimed acceleration time of 3.8 seconds. It was reported that Audi was considering a limited production model (200–500 cars) based on the quattro concept. However, the idea of production was scrapped in favour of expanding the company's crossover range. Audi Sport quattro concept (2013) The Audi Sport quattro concept was unveiled at the 2013 Frankfurt Motor Show (IAA) to commemorate the 30th anniversary of the original Audi Sport quattro. The show car features angular flat C-pillars, as well as rectangular double headlights featuring Audi's Matrix LED technology, a spoiler at the lower edge of the rear window, rectangular tail lights, 21-inch wheels, carbon fibre-ceramic brake discs, bucket seats with integrated head restraints, multifunction