Contrary to what some might say, non-ferrous closed covers do not affect tone. Strings move thru an electromagnetic field that is only affected by ferrous materials, ie, metal containing iron. And no, Ironwood doesn't count. The overall feel will be slightly closer to the strings (about 1mm) given the same spacing to the pole/bar top. The same thickness as a plastic cover like the ones used by EMG, Bartolini, and others. So go ahead, splurge!