im running 595 RS. very happy with them. the RS-R are stickier and have harder sidewalls, so would be worth it over the RS. plus
the RS is discontinued now.
or the KU-36, quite a lot of guys running those. they are about $100 a corner cheaper than RS-R's.
they both handle very well in the wet. i've done PI twice in the wet with them, heaps of grip. i was following a guy running ku-36 on
one of the days, he seems to like them.