Thanks very much for the replies guys. I appreciate the prompt response.
Because these cars cost a pretty penny to repair, i'm overly cautious when it comes to these things. After suffering trhe infamous M104 headgasket leak and 1997 5-speed transmission failure, the last thing I need is a damaged engine!!!
I'll consider checking/replacing the coolant cap, and re-flushing the system using Mb Antifreeze as Duke explained. I question if the dealership properly did this, so i better do it myself this time.
If Radiators aren't to expensive to replace, I may also consider this as well. Might not be necessary, but can't hurt on a car with over 100K on the clock.
I've never seen my car go over 90 degrees prior to the t-stat issue, so maybe i was lucky my car ran no hotter than this. But as I learn more about MB, it seems 100 and above is also normal. I personally find this disconcerting! But I suppose i'll have to accept this as a truth with MB cars.