i do run an 8" invisaleader when i use fireline. i like the swivel snaps on this brand. with fireline i really dislike having to cut the knot each time so i wanted a quick snap, and because i use a quick snap i might as well use a leader. if you give a mouse a cookie... fireline, although very durable, is subject to fraying when pounding on rocks for a while. i use the leader to limit the amount the line rubs on the rocks and generally cut and retie the leader on after a long bit of trolling if i hit the bottom a lot. plus it never hurts to have a little bit of metal to protect your line from the toothy monsters. these leaders are fairly inexpensive so i dont feel bad changing them if they get kinked up. the first fish on the trip this year managed to twist itself up so badly in the line and leader i had to change the leader 150 yards from the shore on the first lake!