The 2006 Audi A4 has 351 problems & defects reported by A4 owners. The worst complaints are engine, fuel system, and lights problems.
Audi A4 2.0 T >> 2008 Audi A4 Reviews and Rating | Motor Trend

Audi A4 2.0 T >> 2008 Audi A4 Reviews and Rating | Motor Trend

The Audi A4 is an improvement over the previous version, but isn't good enough to topple the BMW 3 Series
Audi A4 2.0 T >> Audi A4 Allroad: 2018 Motor Trend Car of the Year Contender - Motor Trend

Audi A4 2.0 T >> Audi A4 Allroad: 2018 Motor Trend Car of the Year Contender - Motor Trend