I've used this kit twice, and it's worked well with two significant issues. First, the snap ring included in the kit is junk. In both cases, it deformed as soon as I applied pressure with the snap-ring pliers; not remotely useable. So throw that in the garbage. The next issue, and maybe the OE bushing is like this too, but I've ended up filing down the end-gap to get the bushing into place and to lessen the radial clearance to the helix. Now the good news. I've run this on my 600 RMK for a season: the buttons look great with no mashing or cracking, and the bushing seems to be riding smoothly. Just did the same on an Indy 500, and working well too.
Shipping was very quick and met expectations. However, part quality was very poor. Snap ring permanently deformed when attempting to install, went back to using the old one. Keyway was also too large, even after doing a little filing - also used old one. I did not use the bushing as my old one was still in really good shape. The only thing I ended up using from the kit was the buttons, although after seeing the quality of the snap ring and fit of the keyway, I am concerned about how they will hold up.