Hmm, do you have an SAFC?
I personally would recommend BCP6ES plugs, without the R. Gap them to 0.64mm.
I doubt it's the coil packs, still most likely plugs, with a combination of running a tad on the rich side:D
Erik, It is the knock sensor, strange it didn't showup on the dyno, but sometimes the road conditions can load up the car differently. Take is back and get them to knock out a bit of timing.
Alan's is an R33 GTR, which use a different set of calipers to the GTS-t's. If there was enough R33 GTR's with interest then I could organise a group buy of them:D