From what I have heard this is the LSD on the Speed 3's.
http://www.gkndriveline.com/drivelinecms/opencms/en/products/torque-management/passive-tmds/torque-sensing/super-lsd.html
http://www.gkndriveline.com/drivelinecms/opencms/en/products/torque-management/passive-tmds/torque-sensing/super-lsd.html