Bob Z - Is that 100k on Boxster clutches? If so, what tranny was that? If clutches in general, yes of course it can vary and I have had up to 150k on a clutch (saab).
Edevlin - Is that the 6sp or 5sp? Thanks! Edit: Just noticed on your signature line that it's a 5 sp. so another good data point.
Blue2000s - I disagree about the dealer being dishonest. I asked him how long do the clutches last and he told me what he has been seeing on average. He said some were shot at 15k and some much longer than that 40k average due to driving habits, etc. Incidentally, he said the 15k one(s) were due to people using the clutch friction point to hold the car when starting on hills which is a good lesson for all of us to use the ebrake!