Here are my upgraded price ideas for them:
Holohraphic Sight= 10000 Gralats.
Grip= 9500 Gralats
Bullet Upgrade= 6250 gralats for 4000 upgraded ammo
Extended Magazine= 9000
Upgraded Mechanics= 14000
Shortened Barrel= 10000
Tactical Laser= 11000 (to keep to many annoying people with lasers)