I tried E 3s plugs about 5 years ago when they were fairly new. My rig was more responsive, quicker down the highway, and then a BIG BACK FIRE and I lost power and sputerred all the way home. Pulled out the plugs and found one completely melted, and a piece of it missing. I put my NGKs back in. But my jeep was still running bad.Took it to my mechanic and he had to take the head of and install new piston rings, gasket, and remove foriegn piece of metal inside cylinder. I went round and round with E3 corporate office. In the end they did end up paying for my repairs. I have pics of bad plugs somewhere. DO NOT USE E-3s.