This
article is for modding enthusiasts who want to save disk space while
maintaining several copies of GTA IV. It can also be useful to create a
single separate copy of game folder for downgrade.
Reducing space taken by GTA IV copy folder
How to make copy for 1.0.0.0 rollback
How to make copy for 1.0.4.0 downgrade with old radio downgrader
How to make copy for classic 1.0.7.0 downgrade with official Rockstar Patch 7
How to make copy for simplified 1.0.7.0 express downgrade with ZolikaPatch