Glad I found this thread. LGT with ACT streetlight clutch kit installed. Went from 28 pound dual mass down to the 14 pound (I think) lightweight street flywheel. Noise mostly heard in 2nd/3rd decel from above 2000-3000RPM. Also sounds like somebody trying to shift into first from a stop without the clutch, hehe. In other words, bad!
Mine isn't as loud as the video and I was a bit concerned. Sounds like others have similar issues.