Each of my Audi A4 wagons has suffered catalytic converter failure around 200,000 miles / 350,000 km which has rendered them uneconomic to repair (at least in California.) But it's about the only wagon on sale in the US (SUVs do not fit in my garage) so I guess I am stuck with them. It seems more economic to buy a cheap one and drive it into the ground (one can buy two used Audis for the equivalent Toyota/Lexus.)