JHF
Driving Dynamics Pro
I think the Audi build a Plus-version. But it's comes after when the RS6 Sedan has released(end of 2013). But I think that too, when this monster goes dynotest, then it has at least +580-620 ps. Same thing what Motortend had tested for the S8.
http://www.autoblog.nl/audi-rs6-plus-krijgt-minstens-600-pk
http://www.autoblog.nl/audi-rs6-plus-krijgt-minstens-600-pk