I owned a 99 R6 from 99 to Feb 2005. They are great 600's. If I were buying another 600 SuperSport I would not hesitate to by another one. I put 35,000 street miles on it and multiple track days and never a problem. Luckily I sold it to a buddy of mine, so I still get to ride it!!
Unless the motor in spinning at least 9,000 on the tach, you and the bike will not be happy. Power is lacking down low, but that's just the nature of high horsepower 600's.
Go for it, the R6 rails in the fast stuff!!