I just used a 6 mil poly sheet from home depot. The original caulk was a string caulking. I just rolled plumbers putty into thin strands and used that. Once installed, it looked pretty close to original. I also sprayed sound deadener in the doors. I think the issue with using a foam is that it will keep the door panel from sitting flush against the door shell. Though on an e-body, I don't think you will have that issue due to the way the door panels screw on. For a b-body using the fiber board cards, it would be more of an issue.