Yes the copper plugs are better and I don't know if the zMAX helps performance but it did make my car run about 10 degrees cooler so it would seem to me like it should help with performance by reducing friction.
I did also notice that the inside of my valve covers were black with a sludge that the oil has left and I just had the valve covers off today and the black sludge is breaking up and the metal looks cleaner.
I put it in my motor in a desperate attempt to lower the temp because it was overheating, it did help but did not cure it, for that I had to put the stock pullies back on.
------------------
James Cox
nochevy@hotmail.com
1991 Mustang LX
12.565 @109.38mph 1.764 60ft