To install: Open Optional folder and move over gamedata to install folder.

Agroprom Underground V2 Endless Spawn: use in subterranean areas. Mutants or stalkers are spawned upon reaching trigger zones that reset after a certain time. 
Optional R&M: Add logic feature to Hip, Wolf, Fanatic and Major, mechanic at the south checkpoint. ;bugged sometimes
Optional D&D: Removes Traders at Darkscape.
Optional A&D: Add a barman to freedom.