I had nology plugs, they were ok at first but then gave me the symptons of a faulty TB. I spoke to Alex at AKS who supplied the plugs, he suggested going back to the Iridium 8s, which I did and that sorted the issue.
Have you fitted the latest PCV and DV revisions? Also how about a Oil Catch Can to prevent inlet port and valve carbon build up?
Also, I'd stay clear of R Tech. I've heard a few bad things from people in the know without a vested interested regarding their mapping techniques. I'd recommend Statller and a GIAC map