Plastic inside doors

I just stripped the interior of my car in preparation for dynamat. The white plastic in the doors, do i need it?

Its intended to be a moister barrier to keep rain out. Basically the btum of the door has holes in it because the seal around the window lets water into the actual door. The plastic prevents it from coming into the car. It's really up to you i guess. I have seen cars without them and they never had water in the car but i can happed.

thanks, man. I guess its staying till i have the bump strips replaced