Well neither the Super Sunfish Add on or the minifish has been made for apx 30 years. The Minifish is a smaller version of the Sunfish and never really caught on. The Super is actually just replacement rigging using a "normal" type mast/boom/sail rather than a lanteen rig. They also added a traveler to the front wall of the cockpit.
Since there's been no development on either since they were made and there's been a lot of "speed" updates to the "standard" Sunfish, currently the Sunfish is actually the fastest, the the Super Sunfish and trailing Waaaaaaaaay behind is the minifish.