I always disconnect the rear track bar from the axle end, but that's because I have an adjustable track bar and fine tune it to the lift I'm installing.

Also it makes the install so much easier to remove the bolt from the drivers side upper control arm where it connect to the axle if for some reason you don't have access to a spring compressor. I think it's so much easier to just remove that bolt then have to mess around with the spring compressors. Takes 10 seconds to remove that bolt with air tools.

Matt mentioned disconnecting the sway bar. I think he was referring to the sway bar end links. I have quick disconnect which makes it easy but all you would have to do it take the bolt out of the upper end of the end link where it connects to the jeep