I just did my AA SYE install and wanted to share my experience. That giant snap ring really killed me, especially since I only had normal lock ring pliers. I tried for about 2 hours too get the original off and finally got it. Then I tried for another 2 hours to get the new one on, but it was impossible. The Lisle 44900 tool only opens about 0.9", so I went down to Napa and got theirs that opens about 1". I still couldn't get it and had to cut the tool to get it to open more. I cut both bump stops up top and 1 handle tip, so it opens about 1.25". You can't really do this to the Lisle one since the long straight part of the handle is their bump stop.
The Napa one on the left and Lisle on the right.
If I knew better, I would have gotten some good pliers like everybody is saying, maybe one by SK, the middle tool in the picture. That mofo is only like $30 online and opens like 2 inches with a neat 4 bar design.