I have a 2000 S also. I get a little grind going into 2nd once in while too, especially when the tranny is cold. Usually goes away after the tranny warms up. It feels to me like the synchro is worn. I have to pause a little between 1st and 2nd when I shift until the tranny warms up. The car just turned 100K, and I am the 3rd owner. No telling how the previous owners treated the tranny. I usually double clutch when down shifting into 2nd to minimize synchro wear.
Did you see this thread in the Performance and Technical section?
http://www.986forum.com/forums/showthread.php?t=18785
They have the same problem.