[Leets]

I've used plenty of cans of Great Stuff. It's "Great" at quieting down the cabin from outside noise, but that rattling sounds like a bigger problem.

Try some generic dynomat stuff (cuz the name brand is a ripoff) to get rid of the resonance. Then make sure your handle and lock rods still have that stock padding around them. Also make sure none of the wire harness retaining clips are broken.