So I am wanting to make a system where the character head rotates depending on where the mouse position is, and have it show on the server.
How could I achieve this without having my game be destroyed by having laggy head movements etc.?
I see in games like The Wild West they have a system that orients more than the head and causes no issues at all, looks amazing. Anyone have a solution on this? I highly doubt they would give away their secrets if I asked 
Just do it on the client in RenderStepped - it will show on the server because the client owns the humanoid parts.
A more complex solution would be to do that and stream the mouse position to the server, so that the server can update the position too. But you don’t necessarily have to do that.
This might be something you want to look at! It allows you to track your mouse and camera with head movement.
If you want to make sure your game isn’t lagging, try running cosmetic scripts locally, never on the server!
Yep. Network ownership handles replication just fine.