If the coil is the fault, it will give one unmistakeable sign. The car will idle ok, but will not accelerate. If you touch the accel pedal, the engine will die. If these are your symptoms, the coil should help you. One thing I have seen alot of lately is the crank sensor. Usually they will just die with no warning and wait 5 min and restart.
Be sure you have an updated overvoltage relay.!.
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM