You don’t have to change your track bar height and can leave it as is if you are happy with the way the Jeep drives. If you have bump steer and want to improve the way it handles, then you would need to raise the track bar AND do a drag link flip to keep the drag link and track bar angles the same.
I’ve got 4” of lift and chose to change both at the time I put the lift on so can’t comment on the difference, do have a buddy who has 4” of lift and has the OEM drag link and track bar mounts. He seems to think it drives great.
Your choice, but do them both at the same time. Also need at least 3” bump stops on front with the drag link flip.