Audi believes the RS5 covers that segment of the market - is working on super RS6 sedan which may feature around 600 PS (441 kW / 592 bhp).
(http://imgs.blackfalconmedia.com/2008/7/medium/9080716.004.Mini1L2.jpg)
(http://media2.blackfalconmedia.com/2007/6/medium/2070626.001.Mini2L.jpg)
No new Audi RS4 to be developed - RS6 instead (http://feeds.worldcarfans.com/~r/worldcarfans/Jxfz/~3/6bv1hqoMynQ/no-new-audi-rs4-to-be-developed---rs6-instead)