Hey Norm,
I won't say that I have fuse rolled, per se, but I did recently put an "audiophile" grade fuse from Audio Magic in the ZMA right after I got it back from Steve with all the internal/external upgrades I had him do.  But it was one of those situations where I figured it certainly couldn't hurt, but unfortunately so many other variables had been changed that I could attribute anything specific to the fuse.  The overall amp sound was noticeable improved, but again, it could have been the result of one or a few changes to the ZMA.