Anyone know about materials for amplifiers?

Question:I'm looking to refurbish my current 4x10 Bass cab. It has a plastic material thingy on it at the moment. I'm looking modify it and put something else on. What would you suggest? What fabrics / things should i use?
Underneath the plasticy stuff is just wood. Here's a pic of it:

http://i44.photobucket.com/albums/f30/oz...

Let me know what ya think.

Answers:
It doesnt really sound like you know much about this sort of thing.
I would leave it as it is, otherwise you will find it will sound awful.
If you are going to give it a try, use MDF. at least 20mm for that size of speaker box.