Benzmac - That seems like a pretty reasonable expense if you look at it as something that needs to be refreshed periodically as preventive maintenance. If Mercedes would look at it as such, it would not be an issue. Which comes to the question again as to how often (time/mileage) this component needs to be refreshed for trouble free operation.

It would be nice if the design/application were changed so that this part failure would not cause the kind of damage it does. However, other cars (Toyotas/Hondas) having timing belts that fail with interference engine designs that also cause considerable damage and expense.