4.2, that is likely a control arm issue. I bet your bushings are worn out.
I thought the same thing... So, I put the car on the lift and shook the wheels, the uppers seem fine. On the A6, when an upper control arm went, I could very easily tell which one was bad. Maybe a lower control arm is at issue? Any way to check without just replacing?
2003 RS6 l SE Exhaust l Koni Yellow Sports w/stock springs l Lowered 1"F 1.25"R l EPL Tuned l 19 x 9.5 VMR V713 & 265 PSS's l 50% window tint l Protective film on entire hood, bumper and front quarter panels l