Quote Originally Posted by JJ91284 View Post
NGK TR55 are actual about 1/2 step colder.

I run the TR55IX iridium plugs and couldn't be happier. DON'T go with NGK TR6 plugs because they run to cold 1.5x colder and your mpg will drop for being stock. I've used both plugs and went back to TR55IX with my current mods.
Technically - yes, but NGK always has shown them to be the direct heat range replacement for the L67/L36. X2 on the TR6 - my MPG noticeably dropped when I ran them, too. I don't have any experiences with platinum plugs - I tend to stay away from them.


-Swash