That is not the PROBLEM of "HOW MANY DEFENDER'S NEED TO BUY" but the problem i could see now is the BEST-PAIR between the two Centre Defender has yet to be nominated.
Just look at MU, Reo and Vidic has been partnership of long time and both of them have created well understanding. Just look at Real, who shall play alongside with Canavaro????
Is that METZELDER??? or Sergio Ramos??? or even Heinze???