I've owned a few of these M102 engines myself, all driven to over 300,000 kilometers (my 87 190E 2.3 is now owned by a friend of mine that's at 500,000).
I changed the timing chains between 160,000 and 200,000 kilometers. None were stretched enough to warrant replacement, but it's inexpensive, and gives peace-of-mind.
If I were you, I'd change the chain and tensioner.
1998 C230 "Black Betty"