1yrs of ownership has cost me about £8500 including this oil leak fix thats pending. (i had another RS6 before this one both C6's so i class my ownership as 2yrs even though its a 1yr per car)
Tyres £1000 i'm on my second set, Brake kit for the front £2500, wheel bearings and suspension kit £650, copious services and plug changes £600, Gearbox fluid change £250
Rear brake setup £1000.. probably other stuff too!
Before my ownership there was the £1500 remap and £1300 milltek... so there's been over 10k spent on her in the last 18 months... but as well as the things done in my signature.
Its well specced,
Elec steering column
Solar sunroof
Blinds
Soft close
Adaptive cruise
Carbon engine covers
Phone handset in arm rest
3Gmmi
TV/DAB
passamger seat memory
high beam assist
And its 730bhp and nearly 800ib/ft so where do you go from that? its a spacious comfortable barge that eats the motorway with east, its also faster than most cars out there and barring its woeful mpg figures it ticks all the boxes of a perfect all rounder.
But yes i agree, they are VERY expensive to maintain, servicing and plugs are easy enough... but things like tyres and brakes and gearbox oil changes are horrendous.
You'll be fine, they are strong cars and mine has has PLENTY of abuse as has Ians and they are still going strong!
Audi RS4 B5 + Audi Q7 4.2TDi
Gone but not forgotten

2017 Mercedes E63S W213 1033/1400nm
2013 Mercedes E63S W212 740/1200nm
2010 Nissan GT-R SVM 680R
2010 RS6 C6 Avant Stage 2 730/1088nm