Spark Plugs and why IK 22's

[Grnarowana]

i was doing some research for spark plugs and Denso Iridiums are the ones i'm getting for my car. However, while I was on Denso's website. I did the criteria search and it brought me:

Premium Class Iridium plug 5304 IK20 .044" $11.99

The price of the per spark plug is not bad. But what i'm confuse is that on the forums people are suggessting IK22's.

So now I'm confused.

Which one is it IK20's--Densos or IK22's on the forum???

here's the website if anyoneelse wants plugs: http://www.densoproducts.com/resultsApp ... tegoryID=1

[Kenz]

I changed mine yesterday. I got the Denso Iridiums from autozone, their part number 5304. First time I have spent 50$ on spark plugs.
It had NGKs in it before.

[Jon11582]

IK22 ONLY if supercharged.
If not, use IK20.