So after reading through several threads from you guys on here, I decided to swap out my current NGK TR6 spark plugs for some colder TR7ix iridium plugs. I did not gap them at all, and just threw them right in out of the box like what was reccomended. My car is an 03 Cobra with a Kenne Bell 2.6H running about 15psi of boost. As soon as I fired the car up I could immediately tell it idled smoother (not that it was bad before) but I could definetely feel a difference. Now the main reason I swapped over to these plugs, was because I was getting a misfire feeling when I would shift gears under load at lower rpms. I was thinking it could be one of several things such as the pprv valve. But I came across some threads on here with people having the same issue, and swapping over from TR6's to TR7ix's took care of the problem. Well I gave it a shot and so far I am impressed! Like I said previously, the car already idles smoother, but it also shifts through the gears just fine without any hesitation! What impressed me the most, is it seems like it pulls smoother and harder under wide open throttle! All I need to do now is go for some more drives to confirm the results, but so far so good