SSK is great if you like shorter shifts. They are almost always a little more notchy than stock, but the shifts are crispy.
I would recommend either a B&M, RD Sport, Autosolutions.com (custom high-end) or ACS (over $800). UUC is good, but tends to be very notchy w/o additional part upgrades. I've heard people that tested all of the above, UUC was not the best out of the box.