[mountainman]

changed the filter and fluid in the tiptronic in the 04 Boxster S LE yesterday. The fluid was not burnt, but was very black with a good bit of sludge in the bottom of the pan. No metal at all. Was able to drain out about 4 liters of fluid and replace it.
I have had no problems of not with the transmission (73K miles) but have noticed that it downshifted a bit hard and not as smoothly as before. I guess you get used to gradual change and do not notice it too much or maybe you just expect things to wear and function differently, but when I took it out for a test drive I could not believe how smoothly it shifts and feels. Like a new transmission. Based on the difference I had, I can't believe Porsche waits til 90K to service the transmission.
One of the best $150 I ever spent. Now the C 4 needs it.