[pennsiveguy]

Many thanks for the great info and general moral support on this forum and particularly this thread. I just did a complete plug change on my n63tu yesterday. I used the X5M plugs, gapped to 0.60mm. No problems at all. I used anti-sieze on the threads and a dab of dielectric grease up the snout of all the coils. I swapped in the X5M air filters too, as the old (original equipment) were pretty dirty. Car runs great at sustained WOT and idles perfectly smooth.

I hadn't experienced any issues so I probably could have gotten another 10-20K miles out of the plugs. They looked uniformly great, just like the one in the image. I think I needed to "bond" with the car by doing some wrenching; it feels good to be able to do something besides write checks. Not to cast aspersions on folks who turn all the wrenching over to qualified techs - there's plenty of things I handle that way too.

I'm contemplating a BM3 tune, so the plugs were also a preparatory step for that. I'll keep you posted; I think everything is in place to make that go smoothly.

Thanks again, everyone. Cheers!