Just Test drove the new rs6. It is a let down compaired to the m5/M6 and made my decision easy to swap the m5 for the  M6 with competition package. 

If some one need an all Year round car, than i can see the rs6, other ways it is a no no. The engine of the rs6 is now were near the engine of the m5/m6, suspension ways all the way m, and personaly the interiour of the M6 matches my tast mutch better

by the way M6 Grand Coupé 100-200 in 7.6 sec in latest AMS vs cls63 biturbo..