It will work but the density will be oh lets say not dense. The sound will suck and you will need 1/2 to 3/4 inch thick fiberglass for strength. the woofer will crack anythinf smaller and the foam wont hold up. now if you need 1/2-3/4 fiberglass them why have the foam in there at all? Its a question of density not will it work.
Terry
96 Eagle talon ESI Star Stage II - Boost/oil/EGT gauges