Noise seems to be from the lightweight flywheel on decel, not the LSD. Had a similar noise from my previous car (Mini Cooper S) with a lightweight flywheel on decel. You learn to avoid the patterns that cause the noise, or you just tune it out.
It seems to me that if the noise were from the LSD, it would occur on throttle, not on decel. My brother has a Subaru WRX with a clutch-type that clunks loudly on throttle in a corner as the clutch plates slip. The tighter the corner, the louder and more violent the noise. You can actually feel the clunking shaking the car. The OS Giken has no such problem. It is butter smooth on engagement. In very tight parking lot maneuvers, if you really listen and concentrate, you can feel the tiniest of clunks, but nothing during normal use.