If you read through the thread I attached you will see that they are not set very 'aggressively' as standard. Constant heat cycles though the VC degrades the effectiveness and they gradually become more and more like an open diff. As new they are about 25Nm but you can get them rerated to much higher settings..
The benefit of the VC seems to be it is MUCH cheaper than a Quaife and ATB - the costs I could ascertain were into 4 figures for a plated one or Quaife fitted new ( see linked post above )