Went on a looooong drive last weekend and picked up an 03 C5 (4.2 Bi Turbo) RS6 Avant in Daytona Grey. It seems like a good one so far, drives well and looks great. I scanned it with VCDS and the only fault coming up is for the navigation because it's been removed. It has had quite a few owners and has just under 130k on the clock, but it's had a lot of money spent on it and seems like it's been looked after. It had a replacement gearbox in 2013 fitted by AMD and hasn't done much mileage in the last year or so. Being a 12 year old car there are a couple of niggles that need sorting:
There seems to be a bit of friction on the brakes and get a low squeal sound at normal driving speeds.
After a bit of hard driving the brakes squeal at an embarrassingly loud high pitched level.
The liquid in the rear view mirror has leaked so will need replacing.
It sounds like one of the rear speakers has seen better days, the CD changer and (I think) the Bose amp have been removed.
The drivers door doesn't close sometimes I think the latch in the mechanism is shot.
The navigation has been removed and replaced with a pioneer double din.
I can't change the date or time on the dash (I'm guessing because the navigation system has been removed, the menu knob by the handbrake does nothing maybe for the same reason)
It has had some modifications... Wagner intercoolers, Milltek cat-back, Billstein Coilovers. The previous owner said it had a stage 2 MRC remap (and gearbox remap) and was tuned to 520BHP. There is an invoice for a MRC remap, but no dyno print out in the paperwork to back this up. It does go though