This highly modified 2013 Audi S6, used by APR for engine management software development, features an NGP "Stage 3" twin-turbocharger kit, APR "Stage 3" ECU tune, and an Akrapovič titanium exhaust system. Finished in Estoril Blue Crystal Effect over black leather with white diamond stitching, it boasts an RS6-specification front end, Audi Sport carbon ceramic brakes, and 21" Klässen iD F53R wheels. The car has 49k miles and comes with a clean Maryland title.