NGK Iridium.., is this overkill Options

[njccmd2002]

these are the ones they recommended for my corolla on http://www.9thgencorolla.com/.

they make for the celi. Anybody tried them....

[alltracman78]

Stock 3S plugs are platinum, not iridium.
1st, 2nd and 3rd gens.
Only the 4th gens might have iridiums, it's a relatively new plug.

As for copper being better because it conducts better, consider this;

Regarding conductivity, do you know how conductive the secondary circuit of the ignition system [plugs/wires/coil secondary] actually is? Both the wires and the coil are several thousand ohms each. This isn't by accident, it's supposed to have a very high resistance to increase the voltage [this also lowers the current]. High voltage, not high current, is what produces a better spark.
There's obviously a limit to this, and it doesn't mean every car runs better on iridiums, many times a car [close to stock anyways] runs best with the original type parts in it.
Point being, conductivity in a plug [under a certain range obviously] isn't as big a deal as most people think.

Copied from Celicatech, I didn't feel like typing it all again.

Also, iridiums have a shaper corner than coppers.
The spark jumps to the corner, not the center.
This makes the spark tighter and hotter.

I'm not a tuner with hundreds of 3S coming through my shop every year, and I don't have any dyno runs to prove anything, but I do know I've had less ignition problems with the iridiums than I did with the coppers.
I also don't run 20+ PSI, and I'm on a relatively stock engine, so I don't see massive detonation.
But neither do most of you.

And you can gap iridiums, you just have to be careful.
The electrode [curved part off the threads that you actually bend to gap the plug] is no different between a copper and an iridium. You just have to be careful of the tip on the iridium plug.