Owned a 96 A6 Quattro wagon for about 5 years.
Drove beautifully, handled the roads and snow like a champ.
Comfortable, good mileage, and solid.
The repair bills were
Drivetrain seals, timing chain/waterpump, you name it.
It was normal for the bills to be $1,500 to $2,000.
I don't think I'll ever buy another non-certified car of this type, and certainly not one without a comprehensive warranty.