I have a 2009 USA EVH Vintage White Wolf --- the tone of this guitar is awesome. It was a hard decision to make. I debated about it for a few weeks. Finally, I email FU and discussed it with them. I mean, who on Earth would wanna change up a USA Wolf ? Well, I went for it ! I ordered a 37mm and the 3 brass screws. It arrived and laid around on a shelf for a few weeks. I went through a few string changes and just never put it on. Then, one day while at work, I realized the time had come to install this thing. I left work a couple of hours early---raced straight home. I was a man on a mission !!! It took about 45 minutes total to install--this included a quick polishing of the guitar and cleaning the fretboard.
Wow, what a fool I had been for waiting so long to install !!
I won't go into the tone because that is subjective to each person.
I have recently ordered a USA EVH Grey Wolf and the FU brass block for it will be ordered next week !!! It is a very good product !!!