you can only prove hearing improvements on the blind a/b tests. blind tests is where all audi'o'philes fail to ID stock fuse from aftermarket and other silly unnecessary stuff.
as you know, fuses tend to blow and usually are all visible on the pcb or direct wiring. the improvement you've heard is possibly from the quality of the contact so all you need to do is to clean fuse terminals with qtip and contact cleaner.
