yes that can all be removed. it will have a slightly louder sound but not much. and it disrupts airflow. so it will help a little bit for now but just save for and aftermarket intake. thats where the difference is.
yea itll just be a little bit louder. but not as much as an intake. youll be able to hear it but not much
and no it wont hurt it. its basically there to make it quiet. when i first got my car that was what everyone was doing until they could afford an intake. removing the silencer and putting a drop in k&n filter. but def get an intake whenever you can