Whether or not you need an SYE depends as much on the Jeep as it does on the lift kit- some Jeeps have issues at stock height, some are fine even with some lift. My 97 was having problems at just 2" of lift. I have a simple transfer case drop on mine, which has temporarily cured the vibrations along with replacing all the joints, but is really only a bandaid fix. The proper fix is a SYE and double cardan shaft- I just haven't gotten around to it yet.
When asking "will this work on my Jeep", don't forget to include the basics- year, motor, axle, transfer case, transmission, etc that are involved- it matters.