The Audi RS6 quattro, commonly referred to as the RS6, is the highest performing version, and top-of-the-line specification of the Audi A6, positioned above the Audi S6. It is a mid-size sports-focused executive car, produced by the high performance private subsidiary company quattro GmbH, for Audi AG, part of the Volkswagen Group.
Both versions of the RS6 are, or have been produced as, a five-door five-seat "Avant", Audi's name for an estate car–station wagon, along with a four-door five-seat saloon–sedan.
A four-door five-seat saloon/sedan followed shortly after the launch of the Avant. Derived from the Audi C5 S6, the RS6 also shares the aluminium structure from the firewall and forward with the C5 A6s with V8 engines.
Official performance figures for the Avant, whilst consuming the recommended high octane 98 RON "Super Plus" unleaded petrol indicate the 0-100 kilometres per hour (62.1 mph) dash would be completed in 4.6 seconds (s), reaching 200 km/h (124.3 mph) in 16.8 seconds (16.6 s for the saloon). Official figures state an electronically limited top speed of 250 km/h (155.3 mph), although most "RS" owners report that the speed limiter is rather liberal on all RS cars, with genuine 'limited' top speeds of 270 km/h (167.8 mph) being possible to achieve. Using a lower octane rated petrol, such as the standard 95 RON "Premium" unleaded will reduce the engine power output, and have logical reduction in performance.
Source: Wikipedia, 2011