looking for something to do in place of the dash speaker.... I'm good with fiberglass, but just can't figure out what to do there.. Any suggestions?

 

Are you doing this for the sake of doing it do you have a purpose motivating the project?

 

For FD ?
I have a suggestion. Sell it, it's worth alot.
But not before you make a mold of it. Then make a solid, flat piece to take up the area. Make a mechanism so it can raise up with a actuator and have a radar detector fold out from underneath it.