Just thought id share this with you. My daughter has a 8520 and she wants a new housing, and asked if i could change it. Ive got a spare 8520 which is new but i guessed i would see how hard it is to take it apart. it didnt take long and ive put it back together. Ive only broken 1 part and only have 3 screws left over, so my advice is this, if you want to change your housing, pay someone who knows what they are doing