The brass block and noiseless spring gimmicks
Lots of people on youtube and online claim these big brass block make your guitar have more sustain, if this was the case, then how come all the guitar gods like Vai, Satriani, Malmsteem and many others do not use them lol
Maybe it changes the tone or even makes it worse. How come Steve who is always obsessed with tone, doesn't use any of these brass things.
Noiseless springs are pure snake oil, maybe they make a bit quieter than regular springs, but is still not as quiet as putting some tissue or foam in there