[Aerkuld]

UPDATE:
I finally got the new regulator mechanism so last night I removed the old one and put in the new one and everythng works perfectly! It was obvious when I got the old assembly out and compared it to the new one that the difference in cable length was significant judging by the length that the compensation spring had extended to on the old one.
It took me a little over two hours working at a fairly relaxed pace to complete the job. However, I did spend ages carefully peeling the adhesive between the foam door liner and the door so that I could stick it back neatly afterwards. Its a pretty easy job as long as you mark the position of the glass in the clamps and the regulator mountings so that you can get everything back in the same position. Well worth the time in my opinion.
This should definitely be written up in Wayne's Boxster/996 - 101 projects book, I suspect it will be quite a common task.