I sold my Audi A4 last year and the engine was still good.
It's the other parts which failed and convinced me to sell the car. The
catalysts, suspension, airbags went wrong.
I was still on the original clutch and the interior looked still good.
Hope this helps

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G. Tarantino - Switzerland
2001 Audi A4 3.0 Q 167,000 km (104,000 miles)
2001 BMW 325 xi 155,000 km (96,000 miles)
1997 BMW 535 257,000 km (160,000 miles) (sold)
1997 Audi A4 Q 247,000 km (153,000 miles) (sold)