Im going to prep my ceiling surface and then lay down some Dynamat. When I get the headliner down, will it be able to go on that, or will it need the fluffy insulation to stick to?

 

Dynamat needs to go on the metal or is not going to do much good.

 

if you are doing a coupe, pay a pro...I have done a few headliners in my time, and a coupe is a major PITA

 

how much is it generally to pay a pro?

 

The dynamat will be fine. You do not need loose fibergalss insulation. The headliner does not stick to the roof. Adhesive is only applied at the edges where it folds over the door frame under the windlace and where it folds over the front a rear window frames. Yes, the correct way to install on a classic mustang is to remove the front and rear windows. However, it can be done without.
Good luck

 

ok thanks. I realize I didnt explain it well. I wasnt sure if the headliner needed the fluffy stuff to hold onto or not.