Its all down to the gearbox and the way the shafts are. The dual mass dampens the noise out, but that is taken away with the lightweight single mass. Mine does chatter a little bit, but I can only hear it with the bonnet open. Non of the chatter noise enters the cabin.
I have some interesting info from Gary at Peloquins. He says:
'
Wave track is a very old type of ramp design and can become erratic upon acceleration
and deceleration due to not having a constant load applied to sun gears. The old 356 used
a set up like this using rollers and did not last. Plus may perform like a Detroit Locker and
start to make noise. Our unit and Quaifes has been around for many years with no problems.
'
He has always been very honest with his answers and just gives an opinion.
Here is a pic of the insides of the new high torque diff that I have fitted to mine: