BURNING SMELL INSIDE THE CAR AND STATIC/CRACKLINGS NOISE FROM THE SPEAKER SYSTEM. NOISE CONTINUED WITH ENGINE OFF AS WELL AS ENGINE ON. SPEAKERS STARTED POPPING WITH SOUND LIKE GUNFIRE. SMELLED LIKE ELECTRICAL FIRE WAS HAPPENING. THEN ALL OF A SUDDEN HUGE AMOUNTS OF SMOKE BEGAN TO FILL THE BACK INSIDE OF CAR AROUND THE BACK DOOR PASSENGER SIDE AS I SAT IN THE CAR. CAR WAS IN PARKED POSITION AT THIS MOMENT N ENGINE WAS RUNNING N RADIO ON. I TURNED OFF CAR AND STREAM N JUMPED OUT OF CAR WAS EXTREMELY FRIGHTENING MOMENT. STILL POPPING SOUND AFTER ENGINE WAS TURNED OFF SO I CALL 911. FIRE DEPT N POLICE CAME OUT N SMELT BURNING SMELL FROM SMOKE N HEARD POPPING FROM BELIEVE SPEAKERS THEREFORE FIRE DEPT DISMANTLE SEVERAL FUSES FROM UNDER HOOD ETC SINCE THEY COULD NOT DISMANTLE THE DOOR PANEL WHERE THE SMOKE WAS SPILLING FROM. THIS WAS EXTREMELY EMOTIONAL FOR ME. I FEEL THE CAR IS A SAFETY HAZARD AND MERCEDES NEED TO PAY FOR THIS REPAIR N DEALER WHERE IT WAS PURCHASED