car performance spark plug question???

There really is no such thing. A fresh spark plug will outperform an old, fouled, incorrectly gapped, etc. spark plug but you will not notice any difference between brands of spark plugs or materials they are made from. ( as long as they are the correct ones for your vehicle )

Common misconception. As long as any plug ignites fuel/air mixture there will be no performance gain. Think of it like matches, if you have two brands of matches and both will set a piece of paper on fire. Which one performed better?

Spark plug for performance? You should get a spark plug for durability and the application. A spark is a spark is a spark is a spark.

NGK.