Don"t know who makes harley plugs ,but do yourself a favor and use e3's instead. You won't be disapointed E3 .36 plugs for evo engines.To be sure go to e3 site and check the cross reference chart for champion plugs.
The stock HD plugs are all that's needed for these engines. Replacing the plugs with the fancy plugs is a waste of money and makes no difference in performance with a basically stock engine. Also indexing the plugs on a stock engine will not show any improvement that is noticable. Leave the fancy tricks to the racing crowd.
Yep, HD plugs are one of the few things your dealership doesn't mark-up too bad. Best to go w/the stock HD set - your pocketbook will be better off for it.
Champion makes the non platinum plugs they are the same plugs as normal champions the rumor of special specs for hd how can you special spec a plug anyways is a not true