Noisy roof during rain storm
 

I was just sitting in my E300TD during a rain storm and noticed how loud the rain was on the roof. I bought this car as a starmarked car and so far it has been very good. Should there be sound dampening in the roof of this car. I knocked on the roof and it had a tinny sound to it but I did the same to the W124 wagon and it sounded like a bank vault door. What gives?