Alternate part numbers
 

So my passenger window occasionally does not roll down and I have come to the conclusion that it is most likely the door latch assembly that is causing the issue. I have looked at ********************************s website for a latch assembly and it lists 3 alternate part numbers for it. The numbers are

8N1837016A
8N1837016C
3B1837016N

I searched eBay and the alternate part numbers also came back to parts of an Audi TT and a VW golf. The Porsche parts are obviously more money, Audi and VW parts are considerably cheaper. They’re all from the same era so I’m assuming it’s all cross compatible. Is this assumption right as the used Porsche part is $140 shipped and it’s used, a new one is $350 and a new VW part is $60 shipped. Can anyone chime in?

This thread may or may not be of help.
http://986forum.com/forums/boxster-general-discussions/78235-door-window-not-dropping-properly-%96-troubleshooting-check-list.html
In my case the M535 alarm option limits my car to the Porsche part.
I has been a year since I looked at this but I am not sure that the latch would prevent the window from going down, but if the latch is the problem try resoldering the connections as mentioned in my thread. If the latch is already out it is an easy fix.