[Revolution]

Originally Posted by Patrick G

Many of the reasons why General Motors installs more expensive life-extending components like iridium spark plugs, synthetic Dextron 6 fluid, and Dexcool 100k mile coolant is not necessarily about performance, but to be able to honor a 7 year 100 mile warranty. The stock iridium spark plugs do not conduct electricity as well as a copper plug like an NGK TR55, but they will have a much more consistent spark at 80k miles whereas the copper plugs would be wasted. The general would rather have longer lasting components so the customer doesn't install sub-par components by accident. In my years of dyno testing, an NGK TR55 is not a step down in performance over a factory iridium plug.

Very well put.