Many won't agree with this, but the SR fuse is vastly superior to a stock fuse.
Live with the stock fuse for 2 weeks, depending on how much time you do in-the-room attentive listening of course. Then pull that fuse out and put the Purple SR back in. Then you will know. I audition components at a time of the day that I am not fatigued, stressed, or bothered. Usually my hearing is best in the morning, so at that time I can listen and hear the differences best.
Of course, the other thing to consider is the overall quality of the hifi components, room acoustics, and focus of attention. The SR fuses are not magic, but they are not "snake oil" either. The Master fuse is one of the best buys in hifi. The Purple is not on that level, but it will make improvements that have earned it's reputatlon.
Anyway, try the two week thing with the stock fuse, replace with the Purple, and the Purple's improvements should be noticeable right away.