Autolites for $1.50 or NGK for a bit more. Both work fine and do not upset the anti knock feature as noted above.
I now have the NGK iridiums but see no difference other than longer life.

 

If I run other than stock....I get fault codes.

 

Blue Lightning per HD shop improves performance but I know you skeptics, dyno results. 2 yr. 80K mile warranty.

 

E3s, seems like more low end power

 

HD brand plugs are made by Champion in an Ohio plant.

 

I'm like that with my boots

 

Anyone run Brisk plugs?

 

What don't you like about OEM plugs?

 

Autolite 4163 (one step colder) or 4164 (stock heat range) work fine and are only $1.50 each. The only downside to these is the screw-in plug at the top, which in my experience will unscrew on its own in time. I put a very small drop of red Locktite on the threads, making sure to cover only a small area, which keeps it in place. This is a direct electrical connection so you wouldn't want to separate the metal-to-metal contact very much by using too much Locktite.

 

Over 10,000 miles on NGK DCPR7EIX IX Iridium Spark Plugs, and they look almost new. Iridium has an extremely high melting point, so they seem to hold up very well in our hot air cooled engines. Be careful adjusting the gap, as the tip is allegedly brittle. About $7 each from Amazon.com.