As I get some time in the upcoming weeks, I will post pics and go into this topic more. Be careful when purchasing any kind of part on Ebay, especially when the price is too good to be true and when dealing with parts like spark plugs, fuel injectors, EVAP system vent control valves and such. There are a light of Chinese-made, counterfeit parts being sold as "genuine parts" and unless you know what you are looking at, it easy to be taken. This is copied from my post on another Nissan forum, ClubFrontier.org:
I just purchased a genuine Nissan #22401-5M015 (NGK #PLFR5A-11) spark plug from Courtesy Nissan to compare to the counterfeit Nissan plugs I got from Gangle Products on Ebay. I'll have some free time in the upcoming weeks and will do a comparison with pics between those two along with a "regular" NGK plug, which I'll probably pick up from Advance Auto Parts or Rockauto. It's easy to see why people can be fooled by these counterfeits, as they look very much like the genuine article unless you really study them. Here are a couple of things that are "red flags" that you have a counterfeit "genuine Nissan" spark plug:
-the part number is wrong. On the end tab of the box, it has both the Nissan part # and the NGK part #. The correct #'s in this case would be Nissan 22401-5M015/NGK PLFR5A-11. The counterfeit plug has Nissan 22401-5M016/NGK PLFR5A-11. Nissan 22401-5M016 is an actual Nissan part #, but it is for the hotter NGK plug #PLFR6A-11.
-The NGK PLFR5A-11 is their "Laser Platinum" plug, which has a solid Nickel ground electrode. If you look at the end of the counterfeit plug, you will see the ground electrode has a copper core.
Less noticeable differences are as follows, which you would only be able to tell if you had both of the plugs to compare:
-the shade of gray used on the counterfeit box is noticeably darker than the "real" Nissan part
-the printing on the side of the box is a little smaller on the counterfeit box and "Q'TY 1" is in italics on the counterfeit box, but not on the "real" Nissan box.
-the cardboard sleeve that protects the spark plug in the counterfeit box fits snugger, is a little longer and a thicker material than the "real" Nissan part's.
-the blue printing on the porcelain of the spark plug is centered on the "real" plug, but slightly off on the counterfeit.
-the metal, threaded part of the spark plug is shiny and silver on the "real" Nissan plug, but on the counterfeit, more of a bronze-tint to the metal and not as shiny.
-the ground electrode has a more gradual bent to it on the "real" plug compared to the sharper bend of the counterfeit's ground electrode
-the center core electrode protrudes more out of the porcelain on the "real" plug compared to the counterfeit's.
With all of those differences, you might think it easy to spot the counterfeit, but, it's not so easy unless you are looking for it. I've been working with and using NGK plugs since 1985 and swear by them, but, if someone gave me a couple of each and I was expecting it, I wouldn't notice the differences unless I knew enough to study them.
Bottom line, of course, is "buyer beware" and "if it sounds to good to be true, it probably is." There are some great deals on Ebay to be had but you have to be careful and know what you are looking at. When it comes to spark plugs, from now on I'll purchase from either Rockauto.com or other reputable part source, like the local Advance Auto Parts, Autozone, O'Reilly's, NAPA and such.