The original Bosch spark plug is a W9DC0. They are no longer made and are replaced by the Bosch 7607. Bosch recommends the 7911 plug which is the "Super" version and better than original. Gap at .032" - .035". It is not platinum (which are generally not recommended for the 560SL). If wires are original, you may want to replace them. Also air cleaner element. Don't forget your fluids like engine oil and filter, coolant, brake fluid (M-B recommends changing it regularly), power steering fluid and filter (in holding cannister), transmssion fluid and filter, and rear differential gear oil. Good luck.