People buying 2nd hand cars should not give unfair comments to the product quality. It is entirely possible that the previous owner used the car with real rough handling and then sold it off after 1-2 years. The result is that the 2nd hand buyer feels cheated. This is really bad in the case of luxury cars and diesel cars as old luxury cars as well as old diesel cars are almost always in a bad condition.
Also, spares etc of old luxury cars are always very expensive.