I refer to what I said earlier...
there should be a cradle in the armrest. The bluetooth adaptor sits in this cradle. Cars from MY06 onwards came supplied with the bluetooth adaptor. Z's before this date, owners would have to buy the adaptor separately.
If the car hasn't got a cradle, insist in having one fitted.
Many owners will sell the bluetooth adaptor separately after selling the Z.
You only need to get the bluetooth adpator and not the specific phone type ones. They are the old style aren't bluetooth. They work by actually sitting the phone into the nokia or seimens cradle.