[donv]

Bad news. Hope it turns out well in the end.

I like your mis-alignment theory, there is little else that could explain this sort of experience. I can't imagine how this sort of mis-alignment (really, eccentricity?) could come about between the input shaft and clutch components. But that should be Porsche's job to root cause and not yours... sounds like an engine/tranny replacement is in order to me!