Manifold heat shield rattle - any suggestions?

[Matt B]

When cold my ZR makes a terribly loud buzzing noise under acceleration. Sounds as if the engine tries to escape
After some research I found that both manifold heat shields tend to rattle. So if you carefully hit the converters with a plastic hammer your can easily hear the rattle whereas it disappears when you hold the heat shields that are wrapping the exhaust manifolds tight with the other hand.
Is that a common issue? I'm asking because all the screws that connect the 2 pieces of each shield are properly seated.

Any suggestions how to fix this? I was thinking about slightly deforming the shields in some spots to get some tension or maybe add some pieces of glass fibre matt/tape between manifold tubing and shield.

By the way, the noise completely disappears when the exhaust is hot. But the first 15 Minutes of driving are a pain for anyone who loves cars...