The RS6 is back. The muscular saloon and estate is due to be reborn at the Geneva show in March 2007, as a rival to the BMW M5 and Mercedes E63 AMG. The current S6 produces 435bhp from its 5.2-litre V10 engine, but the RS6 will have a turbocharger adding about 100bhp to the total. It'll be quick, trust us. In the spirit of previous RS models, the new RS6 is visually low key. Where the S6 has four round tail pipes, the RS has two oval pipes. There are also bigger air intakes.