Very straight forward, depending on number of sets, just need a MGC plus a Co-Res CP-PM is below 1000 users, therefore you require only one free slot, more then a 1000 users you'll need 2 free slots, 1 x CP-PM CS and 1 x CP-PM SS, can't remember whether you'll need to convert the DB from R25 to R4.5 or whether you can go straight, either way it is best to check in the NN43041-464 - 03.06 Document, the full procedure is explained in there.