If my A6 is anything like my last A4, they are prone to wishbone bushes wearing around 80-100K miles.

Before I put the car in to the garage, I just wanted to check what are the usual culprits for vague steering, nothing feels particularly loose, but the power steering would probably hide that anyway. Tracking is out (outside of both front tyres worn) so that needs sorted and will be part of the problem, anything else to pay attention to?