Dave, Travish,
The part number stamped on the drivers door latch is 193 723 01 01. This number DOES NOT cross on ANY of the 5 online Mercedes Benz parts vendors using 2004 SLK 320 for the year/model. This is the SAME scenario I went through with the drivers door lock actuator (also discontinued, also stamped with a part number beginning with 193, also wouldn't cross to a Mercedes equivalent/matching part). MB parts for models plat formed on the R170 chassis would start with 170 (I believe).