You want to cut off the threaded part of the plug and get a good look down at the bottom of the insulator. You want to have a nice ring of brown/tan at the base. The top part is not telling you richness or leaness just how hot it detonates.
Thats why is called Plug Chops i guess, cos you need to chop the plug. I had a good guide somewhere, if i find it i'll post it up later.
You can buy a new Torque drive part only instead of a complete rear pulley to remove the restriction, i take it the restriction is on the moving face?