This may be way off the topic since I don't know a great deal about your car but check your battery.
The last time I had a nasty sulfur smell coming into the car it was my alternator over charging the battery. The battery was getting soo hot it would cause the acid to boil and create an awful smell like rotten eggs.
I found that my voltage regulator had gone bad and I simply bought the part and installed it on the alternator. I believe cost was $70.00 and the installation was very simple on a 190E.
02 C32 AMG
84 190E 2.3 5 Spd