Timmyboy either misread your question or doesn't know much about the 99 xp limited. Top speed is 55-60 mph. Anyone who's ridden Seadoo's 947 135hp 2-stroke engine will agree.
I think timmy was joking around....but I agree....with no issues I would say 55mph is about right, speedo might read more or less but on a gps 55 is what I would expect. I have never owned one, but have been on a few.