Evo 6 Spark plugs
 

I'm in the process of trying to replace my spark plugs and diagnose what the problem is, I recently pulled them to find that they are the NGK IGR7A and two of them had turned brown at the base of the white ceramic

http://img229.imageshack.us/img229/6383/dsc04789dx9.jpg

first off can anyone diagnose what the problem would be for this to happen?

the two plugs that were discolored came from the two cylinders closest to the passenger side while the other two plugs had no sign of it.
When the car was running you could hear a ticking sound at idle from the side with the discolored plugs
Mods are: Ralliart ECU, fuel pump w/pressure regulator, 3in turbo back


Now that i'm trying to get new ones it appears that the IGR7A's dont show up in anyone's system, but the IGR7A-G's do (which is the Evo 8 plug) and i've got no idea what the difference is.
Can anyone recommend an Iridium plug that i could use?

Thanks for your time and help with this..