after 30k on these plug they looked about as good as can be. There was a bit of oil on the rear trailing ones threads and another had a bit of green on the tab and a bit on the circumference. what is that?

BTW, change the plugs when HOT. Broke free instantly.

 

I would not change plug when hot. you taking threads with the plug cuz the metal is soft. besides expansion of metal makes it even worse.

 

I have always changed the plugs hot on all cars and have never had a problem breaking them free and have never damaged anything. The one time I tried it cold--3 weeks ago on the 8--I could not budge them, and, had I stayed on it, would have definitely broken something.

 

Anti seize stuff on the plug threads before you install them helps a lot when removing them years later.

 

The plugs shouldn't stay in there long enough to seize. However, a drop of motor oil on each of the threads should work fine.

I've never paid much attention to engine temperature when changing sparkplugs. I've also never had trouble removing them. I had to put about 50lb-ft on one of them to break it loose, once, but it did break loose. If you're not using a long-handle torque wrench when tightening anything to spec, or when loosening anything that was tightened to spec, you're doing it wrong. The torque wrench will tell you if something is seized -- your muscles are not a reliable indicator.

The sparkplug shell is galvanized steel, and the engine block is aluminum. Those two metals almost never seize together, especially if the threads are oiled.

 

Make sure your using a wobble fitting when wrenching on RX8 spark plugs, the bottom rear wont fit just right if using a straight extension. Good chance you will slip and crack the insulator.