Tiguan Haldex diff

What is your question?

I have a 2011/12 tiguan 4 motion DSG 7 speed. I devolped a grinding noise in the rear left wheel I assumed it was a wheel bearing but upon investigation I diagnosed the fault with the rear diff. When the car is on a lift and the car is started and put it in drive you distinctly hear the noise from the diff assembly and alumium dust comes from the left side where the drive shaft is connected. also you can phisically feel movement when i shake it. It is obvious that the bearing has collapsed. Rather than just replace the bearing as I am concerned there is internal damage I will bite the bullet and replace the rear drive unit with either a recon or new one or low mileage 2nd hand one.(some advice as to where in Europe I could purchase one cheaper than the £2000+ VW want). My biggest concern is that the haldex unit comes with a new assembly does this have to be coded to the car or alternatively I could fit my Haldex to the new assembly