The biturbo 2.7L V6 (the same family as the B5 S4 but with larger K04 turbos and ~380 hp) is strong, but the turbos are widely reported to fail around 50-60k miles regardless of care. Budget for it and verify turbo health (shaft play, leaks, whistling under boost).
The 2.7T's turbos are a known wear point
Audi RS4 (B5) · mechanical