One of my four spark plugs has the metal from inside of the boot rusted onto it when I was checking my plugs out. So now I ordered Magnecor spark plugs wires from Mazdatrix and all new NGK's lol

Ive seen that before. Its even more fun trying to dig it out of a coil after wonder why one coil isnt firing. Turned out a previous spark plug wire from the first owner broke inside and rusted.

Just got it all put in and damn it made a difference, those plugs and wires were nasty.