Does not have an ejection port door, nor any provisions to add one, cannot be done. No forward assist, nor any provisions to add one, cannot be done. Brass deflector IS standard equipment on all Carbon uppers. Trigger guard does not flip open, it's molded into the lower receiver and cannot be altered (I suppose it could be dremmeled off and epoxy'd back on), but it does have generous relief for gloves/large fingers. Lowers will take most aftermarket performance triggers, but I don't personally know if Chip's modular trigger will drop in.