The proper plastic or fiber replacement pans (not sure what they're made of), are expensive. $225 or something.

I was lucky, a Benz repair place had one, almost new, for $10. I learned that when you take that off, have something under it to support the weight, otherwise the areas where the screws go in will ultimately bend over and over, and tear.

It really won't help much with sound, but more importantly, it will keep water off of your electrical components during rain storms!