Uhm, just a little quick brain storm here:
Holohraphic Sight= 3500 Gralats.
Grip= 3000 Gralats
Bullet Upgrade= 2000 gralats for 5000 upgraded ammo???
Extended Magazine= 2750
Upgraded Mechanics= 3100
Shortened Barrel= 2500
Tactical Laser= 4000 (to keep to many annoying people with lasers)