CR8E and CR9E spark plugs?

I discovered that I am using CR9E spark plugs and not CR8E. mine one is 3LN3 model, I think CR8E is suit for my bike, right?.
What is the different between those 2 plugs? and any problems if I keep using this plugs? thx.

 

I use cr9e's to thay run a bit cooler ie for big runs or thats what i think any way

 

This might help - With the heat numbers I believe it is 100deg difference per number

http://www.ngk.com/sparkplug411.asp?kw=Complete+NGK+racing+plug+number+chart&mfid=1


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