My blazer came with some home made panels made from 1/4 hardboard (simular to MDF).
I would say this will be heavy enough,
after I mount it a little better- right now it's not mounted very well and seems a little flimsy.
I plan to mount speakers in mine too, and I will be "beefing up" the panel around the speaker locations & will probably use 3/4 MDF there. I'm trying to come up with some type of pattern to dress it up a little- I just have a little "creativity block" but I'm sure I'll come up with something.
If anyone has any unique designs on their panels please post pictures- I promise to only use your designs as inspiration!