they are about 5 years old and I have a slight "disturbance" at idle. When you feel at the edge of the rotor, you can feel roughness. The metal spots at the cap also have a black horizontal dash, i.e. burnt copper. I hope the picture shows it. The plug wires (I know it's not the wires but the plugs at the end) are all above 1300 ohms resistance and they are silicone, not copper. I will replace them with Beru's.
I put in already new plugs when I took the pictures and measured the resistance a few weeks ago.
I'll put some dielectric grease on the contact points and that will hopefully take care of that slight unevenness at idle.
Any more tips or things I should do? Grease the rotor shaft?