1997 E420 Timing Chain

[NeedHelpMore]

Hi,

I just talked to my dealership and they want to check the timing chain to the tune of $200. If it is bad it will cost $1,200. My car has 98,000 easy miles.

They Recommend:
Changing timing chain $1,200
Changing ball joints $360
90K service $425
Repalce broken window regualtor $400

It is there because the rear windo w stopped working (regulator).

Are broken timing chains common in my model and at this mileage?

I am not sure what to do??

Thanks,

Christine