[RedEye]

I had some success by filling the space between my outer pipe and inner baffle with high temp silicone. (red stuff). Silicone has traditionally been a good material for vibration reduction.

I used probably 8-10oz of the material, in 4 different injection holes, and let it dry for a few days. Turned out I should have let it dry for probably a week or two. It's been mildly effective to reduce vibration noise, and is my cheap last ditch effort to having new pipes made. Might be worth a try.