I tried purple fuse in my DAC (Bartok at the time) as I read thats where you can hear the most improvement.I have purples in both May and bliss. Though i can’t say for certain they do anything special. Haven’t bothered to replace fuse in the Envy
I think it did improve clarity a little but not too much of a degree.
I'm always a little wary of swapping something like a fuse as it's basically a safety device to protect the equipment.
Of course people have been replacing them for years and I've not heard of any units being damaged. Just make sure you have the right fuse for your region!
As I understand it the SR "master" fuses are meant to be excellent but a little pricey.