Back when the cars had just come out, I went with the Nismo flywheel and clutch, which had a single mass dampener, and found that it was very quiet, had the same basic issue Randy pointed out which is mild chatter at the 2,000rpm range (depress the clutch and it goes away), and concluded after getting used to it that it was a wonderful improvement, but not enough. The car should have come stock with it.
I have now switched to an Exedy Carbon-Carbon lightweight flywheel and clutch, and now am much happier with the results. The clutch on that unit is wonderful. Going to track it on November 30th at Laguna Seca and then will really know what it is all about as a unit. Single disc, so plenty of clamp power for FI. Not any noise issues so far. Still getting used to it as the entire assembly, including the clutch, is only 28 lbs I think. Rev matching is a dream with this unit.