Details with pics you can see on my webpage.
Do NOT buy the material from Headliner, it is too thick.
I bought the material thru a friend in Germany.
The BMW headliner material is 3,2 mm thick including the foam.
For the pillars you do not need the material with foam.
The headliner (company) material is double thickness, mainly used on US cars. You will have special problems when you have a sunroof.
Also at the edges it is difficult to arrange that thick material.
Any good shop for headliner material can supply you the correct one.
I even had to send in a small sample from my old one, so that they were sure to deliver the correct material. They had about 1.500 different kinds and colors.