Steves right on about the ground, especially in a stage only model.
With the buzzing on the high notes, bending the brace is a quick fix. Feel free to forcefully pull on the metal brace that goes between the tonebars, pulling left or right in the middle of the brace until buzzing stops. If you can wiggle your tonebars left and right though a good distance, then Its probably best to replace the grommets, the black rubber things between the screws and the tonebars. They help hold the tonebars in place.