+1 with Alex. I have a cusco 2way set at 60% too. I left the original 100% locking it came with and was too snappy for road use. The best discovery I made recently is the motul 90PA LSD oil. Almost gets rid of the chatter/clunking and its now smooth as butter.
LSD is one of the best mods you'd ever do to the zed.
I bought my cusco cheaper than market price if not would have got the Kaaz with WOC coated plates for quietness and longevity but so far there is no visible wear on the plates.
Tomei sells a combo deal of LSD and 3.9 FD and a good price.
Where can I get the tome combo?