I've got the Platinum 4's. Have had them for about 7k miles. I love them. They clean at a real low temperature, so after one practice run at the track, I can feel the plugs cleanliness. I've had no problems, no rough idles, no misfires since I put them in. And yea, I'm not taking off the plenum either, so I had them put in at my 30K service.
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