[onewhippedpuppy]

I did some research on the S6 before buying my S8, they have some similar issues. Regarding the transmission, conventional wisdom says to change the fluid and filter at about 80k then every 40k after that. If I remember correctly that was based on ZF (not Audi) guidance. There's no such thing as lifetime fluid. Otherwise they seem to fail (if they're going to) in the 120-180k range based on the reading that I did.

Suspension bushings can be expected to fail before 100k, but the same can be said for every Audi, VW, BMW, etc. A high quality kit to replace everything up front can be had for around $500 on the S8, I assume S6 pricing is similar.

Had I been able to find a nice C4 S6 Avant I would have been all over it. With it being an older car they all seem to have 150k+ on them, and many have lived a hard life. Great cars though, the turbo-5 is fantastic and damn near bulletproof, even when making silly HP.