Hey Compass1,
I had two areas of vibration similar to the one that you described. For the first one, I ended up putting a large screw-type hose clamp completely around the heatshield (re: after having tightened all possibilities to no avail) and that was able to do the trick.
The second vibration came from an aftermarket header that was abutting the variocam cover w/c I was able to creatively muffle using exhaust wrap and two screw-type hose clamps.
Good luck and let us know what you find.
