[MiloXC3]

I don't know what upgrades are compatible with it but I can't imagine there are as many as a Warrior L96's upgrades, unless it's a clone.
Try wrapping the inner barrel with electrical tape. It will increase the accuracy!

P.S. Make an intro post in the Intro section (forum rules)

 

[MiloXC3]

barrel and hop up. Do the barrel spacer too, that's the cheapest way and it is very effective.
Also what is your fps? You will need heavy ammo if you shoot high!