I think you are looking at a lot more than just this part....looks to me to around, I don't know, $2000 in work and parts. That part doesn't shear like that, I looked at it carefully...that's a stress shear, that means something caused a continual, yet short lived, out of balance condition, I suspect the cam shaft has an issue. Possible journals on the cam, unlikely, but there is no way you are going out of this without doing some cylinder head work...something is wrong there. That kind of stuff just doesn't happen to a Mercedes unless the previous owner didn't install stuff properly...that could be too....this is not junk metal....someone did something wrong to cause that..that doesn't happen on these cars...