Originally Posted by brusk
Some of the guys are starting to use the ngk laser iridium ILZKBR7A8G plugs in their N54's. Might be worth a look as it's a single electrode style for I believe about 10 bucks each.
It's not plug and play though with the N54 and I'm sure it would be the same for the N55. There are threads on E90 post where people found the proper gap to run them on the N54, but I haven't seen anything for the N55. I'm sure someone could get them to work on the N55 you'd just have to be willing to experiment a bit with the gap.