Review on NGK (6341) BKR5EIX Iridium IX Spark Plug: Enhanced Performance and Durability, Pack of 1 by Danny Poulin

It's time to change the candles on the woman's car (Scion xB '06); its mileage dropped and inspection of old OEM copper spark plugs showed significant wear and ridiculously large spark gaps. After sifting through options that would fit their car, I settled on NGK iridium spark plugs. Of course, they are slightly more expensive than OEM specification copper connectors (NGK BKR5ES or Denso equivalent); In fact, they are almost twice as expensive. On the whole, however, they are cheap. A set of 4 costs about $30, which is a meager sum for something that plays a central role in an engine and for parts that will last for many years. Saving half of that by buying copper candles didn't seem worth it. Out of the box they are spaced in the range recommended by Toyota for this particular engine (0.7-0.8mm), which is useful. Installation was no different than any other spark plug on the planet, no problems. I used Permatex Anti-Seize on the threads I had on hand from a previous order. Unfortunately, the new plugs didn't turn her crate into a 500hp fire-breathing monster. That's a little disappointing. ;) However, the engine is now idling and a little quieter. Let's see if her mileage returns to expected levels within the next few tanks. I'll probably take the spark plugs out to see how they perform after 10,000 miles or so. I will update this review with what I can find at the time.