horist

I just put TR6s in my car and several people have told me that I'll experience a performance loss NA due to them.. I haven't felt anything (haven't drag raced either though), but just curious how much HP I can anticipate losing do to the colder heat range plugs.

Patman

You won't lose any HP at all, these plugs simply foul out sooner. I had TR6s in my car when I ran my 12.68, there was no power loss at all compared to stock heat range plugs. They only lasted me 13k though.