I recommend 80K. I changed mine at 65K and it was, admittedly, too early.
Check the tension of the belt and make sure it is not stretched (they make a tool for that IIRC) and if you visually check the belt, make sure you check the whole belt if possible, not just one section.
I think the belt on these engines are very stout and can probably hang until 100K but have your AAA membership paid up so you don't get stranded somewhere if the belt does go (I tend to believe that the engine is non-interference after reading first hand accounts).
