I replaced the plugs about 2 months ago on my 2004 530i... I went to O Reilly's and they looked up on their computer which plugs were recommended for my sled. I ended up getting the NGK Iridiums and what I took out were NGK as well with about 50K on them... The plugs that I took out had 4 electrodes on each plug and the new ones I put in were only singe electrode. This has kind of been bugging me a little but the car runs just fine.. Are there any problems with replacing the 4 electrode spark plugs with the single electrode plugs?

 

If the plugs match the specs for the car then you should not have problems. As the service intervals increased between plug changes the technology needed to change to make the plugs stay in gap spec for the same period. With one electrode, each spark goes to the same ground electrode and after time the metal wears away and the gap gets bigger. With four electrodes when the spacing to one electrode gets bigger, the path of least resistance is to the closest electrode, so it jumps to another of the four- and so on.
The plug theoretically can last four times longer than a single electrode plug. Utilizing different metals like platinum, iridium, etc can extend service intervals as well.

 

i wouldnt sweat it. you wont notice a difference. if they are platinum tipped on both ends of the spark, then they'll last a long time.