Sadly i think this could be a bit too Over powered with the effects, Also there would need to be 2 new textures for the dart gun including a model for it. Sadly i think this maybe a bit too much work for one item.
The effects are okay but they do go on for a bit too long, this can give players who get Dart guns major advantages in melee and gun PvP.
I sadly don't think this item will be added to the game. Sorry.