at work my computer, all data, says that my gtp took iridium plugs originally. my boss whos ase certified but not a high performance guy says you should keep using iridiums and you might get away with platinums but never ever use copper as they will burn your coils up... im baffled. i dont know this much about plugs but in the safely modding thread it clearly says you can use copper. so whats up here? is using copper gonna screw something up and also if i decide to get a colder plug can i still get a colder one in iridium or platinum or do i have to use a copper core?