All three should use Stuffit Expander. If they don't, or they are missing, use the Edit button to change them, and browse for your copy of Stuffit Expander. Select it, then close everything, and the next time you download, it is worry free. Make your Mac work for you. Some MacOS 8 features will remain.
Menus are still sticky.
Windows still shade. Other features remain, but some bells and whistles are gone. The speed gains can be impressive. Includes commercial products, not just shareware. These do NOT include beta releases.