I have run the ND iridium IXU22 for over 5k miles with no problem. Color is good and there is no evidence of detonation. Pricey though.

 

Did 10K sofar with SplitFire sparkplugs
no problems whatsoever.

'99 FLHRCI
S&S 510G cams
SE pro performance exhausts
PC111 USB
AN Big Sucker

 

I run Autolite 4164's with no problems. I even get them cheaper than the HD plugs with my discount at work

 

I steer away from them for this reason. Quote froma clip I saved out of anauto service trade magazine a few years back.

"SplitFire Settles FTC Charges:.....The owners of SplitFire branded spark plugs have agreed to settle Federal Trade Commission charges that "economy, efficiency and improved performance claims were false or unsubstantiated"... an agreement with the FTC bars the company, SplitFire Inc. (Northbrook Il), controlled by Old World Trading,from making deceptive claims about fuel economy, emissions, horsepower, or cost savings...(and) will be barred from misrepresenting the results of tests, studies or research and from misrepresenting testimonials"...the agency alleged that the company "did not possess and rely upon a resonable basis to support the claims, that SplitFire's claims that surveys confirm gas mileage increases were false; and that SplitFire did not have reasonable basis to claim that (its) testimonials... reflect the typical or ordinary experience of customers..."

 

FWIIW HArley Plugs are made by Champion

Your $s Your Choice

 

I know where some of the Denso plugs are made, right up the road from me. Try looking at the country of origin on some of your components.

 

http://www.harley-performance.com/ha...park-plug.html

 

Interesting topic.

Can anyone here that runs other than HD plugs list the benefits/advantages of running the plug of your choice aside from cost ,and if you have found that the heat range is exactly the same as the HD plug and also how you arived at that conclusion.

 

I use NGK Iridum( DCPR7EIX ), they make me think the engine runs better, but basically its likely there that the benefits stop (In my head that is). There may be a chance that they are less likely to foul, but then I never had a normal plug foul on a modern engine, they may last longer but thats no good since they cost twice as much.

So I guess to sum up, there is no reason at all why I throw money away on expensive plugs, and what is worse is that I'm about to install some super dooper aftermarket plug leads as well. You cant knock me for my determination to throw my money away.

 

NGK/ND Iridium's get my vote.... High quality plugs with a good reputation of highperformance without resistance problems.