It was suggested as a compliment to the Jaguar CDI for best performance.
i asked for THREE reasons! not one!
ok, iridium plugs are designed to be fitted to engines such as mitsubishi V6's. they have a service life of 100,000 km.
the rear bank of cylinders on a mitsu V6 is under the intake manifold. this requires a lot of work to get to the plugs. way to much work for every 10,000km service. the front plugs are standard. the rears are not.
theyre also used in modern motors for the same reason...they reduce service intervals. when you see where some manufacturers place plugs nowadays, youre thankful for not having to change them too often.
they also can be run a lot hotter than standard plugs, as platinides have the highest melting temperatures amongst most metals. that is platinum, rhodium, iridium... theres a few others that id have to refer to a chart to recall
platinum i believe is roughly twice the value of gold. its the most commonly occuring platinide. iridium? double the cost again.
meaning the plug is expensive.
there are no performance benefits. a spark in a cylinder is a spark, no matter what. it does the same job regardless.
good decision. just stick to standard NGK "B" series...