Installed a set of Autolite Iridium plugs in my 2001 V70 T5 last December. The car developed a miss around 4,200 RPM after only 3,500 or so miles. As this is my first turbo experience, I learned that iridium plugs don't fare well with the temps in a boosted motor. I switched to Bosch Platinum in Feb. and got about 4,000 miles out of those. This time (from advice on here) I went with plain ol' copper plugs (Champion). Sure enough, I'm developing a miss again. Each time, fresh plugs have solved the problem, and the plugs have been fried every time. It there any reason for this? I don't think that I would be running lean, but it's a good chance since I do have 2.5" turboback with only a dynomax race muffler on there. Any ideas?