Modder and SRK forum member MarceloAbans is testing button silencers for Sanwa 30mm buttons. This is an interesting development, considering the loud nature of Sanwa buttons and the subsequent strategic advantages of having a quieter stick (i.e. your opponent can’t hear you hitting your buttons if you happen to be heavy handed). We at FYR love to see community generated solutions like this.
Here’s a demo of the silencers in action!
more info here!