Merc doesn't specify plug wire resistance. But... There is a note in service manual 18 to replace if it exceeds 30,000 ohms. so...
1. 14,620 ohm
2. 12,790 ohm
3. 15,550 ohm
4. 13,160 ohm
5. 12,400 ohm
6. 36,500 ohm
Coil wire: 6,610 ohm
So I'd say 6 is to be replaced... so they'll all get...