RS6 owners, warts and all please.

[sjc]

Seriously considering an RS6Avant and I'm due an extended test any day now. At the moment I have an HSV GTS-R for fun and a old Mondeo Estate(on it's last legs!) for work and it might make sense in selling both and buying a car that will do both jobs.(Must be an estate).So owners the good and bad points please,real world maintenance costs (approx 15K miles PA), anything I should look out for and the general reaction you get driving the car, as the HSV gets positive thumbs ups everywhere as did my previous TVRs.It's a very big decision for me because, A;the cost,B;I absolutely love the HSV and C; I always bloody dither about these things!.
Many thanks in advance.