C5 A6 especially 4.2's are aging pretty well and look better than most new cars. Most people are shocked that my car is 8 yrs old.
Newer 5 spoke 18" Audi wheels in place of the 17" pieplates and led tailights really freshens up the looks.
Look at Boston Driver's recent post of pics. A prime example of C5 A6 timeless beauty!

Back in Action, transmission fixed!
2000 A6 4.2 V8 (A6 Hulk)
Silver, Royal blue & Vanilla (rare)
5 spoke RS6 Rep 18's
Chrome side mirrors
Rear window spoiler
Modded Upper & Lower S6 Grill
Led tail lights, window tint 35%
Dual rear foglight mod
Led bulbs interior & exterior(so many!)
Resonator delete with chrome exhaust tips.
H Sport, front and rear
AIR horns with stock (fun)
JL Audio 1000/1 with 2 12" Fosgate P3 (too much too loud!)
Clear corner mod, (simple!)