This A4 wagon represents the best of breed for B5 generation powertrain in terms of longevity -- the V6 wasn't known for cooking oil like the 1.8T or popping turbos like the 2.7T, and the manual transmission was designed to last for decades (although the seller admits this one does grind 2nd gear if you try and shift quickly).
The 2.8 liter V6 wasn't a bad piece of engineering, the 30 Valve (3 intake, 2 exhaust per cylinder) DOHC setup was modestly tuned at 190 horsepower and 207 ft-lbs of torque from the factory -- not exactly a screamer, but decent for the late 90s early 2000s.
Audi interiors from the B5 generation featured many high quality touches, but expect the rubberized paint on some switches to have degraded by the time the car hits 219k miles (like this example). In this car the leather seats look decent and the S-line "sport" steering wheel doesn't look too chewed up. Honestly the big maintenance items on a high mile Audi from this generation is the suspension, and the seller has done much of that within the past 20k miles
See another high mile Audi still terrorizing the streets? firstname.lastname@example.org