I highly recommend this video for repairing a door latch mechanism: • Door Lock Module Repai...
It is best to use a correct Porsche part to replace a faulty latch. Many people have had success with a similar, much less expensive VW/Audi part. I originally posted this video a few years ago. After posting it I found that some inexpensive latches with VW part numbers worked great for the Boxster window functions, but not for the electronic (key fob) lock functions. I now repair these with the mechanical portion of an inexpensive latch and the electronics of the original latch.