I have a fren owned a E250 W212 facelift, spend RM60k to repair although bought new and service center say those parts doesnt cover under warranty... fulamak..
In general, German always push the latest tech into their cars, it is common to have certain amount of reliability issues, and German spend more cost in interior and need to cut cost else where, thus you can find plastic parts under the hood. Not only save cost but also reducing rattle sound. Plastic and rubber have less rattling sound then metal..

I have nothing against conti car, really nice to drive and refined.. just that you need a lot of love to own one... and it constantly broke my heart.. hahah