I did find find some plastic speaker boxes at CrutchField.com that are used for Jeep vehicles, called Mod-Pods. They take a 5 1/4" speaker.
Found out how to remove the center belt...drill a small hole in the buckle dimple pictured in 3rd foto. My 2009 buckle did not have a dimple so I drilled a 1/16" hole in the exact same place as in the foto. Then insert a paper clip & bingo they seperate!