The Echo1 P90 isn't a JG. It's a Kart (same brand as the M14 EBR and newly released M14 JAE-100), with metal upper and everything...
Echo1 removes trademarks, sometimes regreases/reshims internals and changes the springs. That's about it. But note that Echo1 rebrands Kart, Well, JG, DBoys, etc... not only JGs.
Hope that helps
