"The reason I made this pack is because the most Stalker packs I found were total crap. So I added a few things like friendly and enemy NPCs and deleted the crappy NPCs.
Download the file -> extract in addons. Normaly you'll see the map called "New Stalker NPC's". If you do, fire up Gmod and look at your spawnlist. Goodluck, have fun.
Now you can do assaults with mercenaries on Freedom :)
My apologies for the broken materials and a few lost errors, before Garry did a few major updates they were working quite well. The exo-suited NPCs still work fine though.