Spark Plugs?

[ak]

I was checking out my owners manual and it lists two different spark plugs for uses. ONe is recommended for normal driving and the other is recommended for highway use. The part number is different slightly, so I'm suspecting the heat range is different? Anyway, strangely enough, I didn't find this in the faq. Which type do you guys use? What's more optimal for aggressive driving style?

 

[ak]

ttt

 

[Bruce]

NGK PFR6N-11and NipponDensoPK20PR-L11, they both have the same heat range...if you want to run colder plugs the number goes higher with Japanese plugs.The stock(hotter)plugs should be more responsive, running colder plugs are better for running in the upper rpm band, and have a rougher idle.Idleing too much on colder plugs will eventually foul them and render them useless. I'm playing with the new Iridiums that are now available. As for you guys running SC or TC should try closing the gap just a tad.The higher pressure makes it harder to jump the gap, you may or may not notice a difference.