I have gone the reverse route. I did fit these plugs to my Sportster, the cost was a blow, $25.00 per plug (in the UK)
On my FXR i tried NGK ($4.00) cant tell the difference. To my way og thinking a Harley engine is not a highly tunes swiss watch of an engine so it dont need balls out spark plugs. Dont get me wrong here i love my FXR but a works MV it is not. At $4.00 each i can change them four times a year, not that there is any need to
I have them for the EVO FXR i'm building, havn't run them yet but have run them in other engines. didn't notice any bad effects. I did some research on the internet before buying them. i paid about 10 bucks a piece for them. anyway, all that i have read on them is that they are not necessarily a Hot Rod or high output plug they are more of a plug that has a much longer life that a standard plug. the other thing that i read was that they are much easier on your ignition system. they don't have to pull as much energy to fire the plug. I'm not an expert, just thought i'd share what i found when i researched them.
Linear Mode
