The 318is has had broken front door trims since we bought it earlier in the year, with an entire centre section missing on one side.
I finally found a reasonably priced set of four door trims (A$200).
Although they were in excellent condition, because of differences in the door mounted speakers, I chose to remove the leather centre sections from the new door trims and fit them to the old door trims. This required the use of plenty of hot glue, and many new clips.
The finished result is very good. Now all I need is some 318is 4-door sports seats.