#1
Im not sure if thats what they are called, but I was wondering how these work. I want to keep my guitar constantly in tune because I get bend happy a lot, as well as use the tremolo bar quite a bit. Are they bolted onto the neck? Are they easily taken apart?
#2
I think you are talking about a locking nut, in which case to have one installed would require a luthier or possibly an entirely new neck. Another option is locking tuners, graphite nut and good string trees. Those will help a lot if you are having tuning stability issues.
#3
Get some nut sauce and lubricate the nut. If the guitar isn't designed for a locking nut then it's no simple task to put one on. You can also get locking tuners. But in my experience it's usually an issue of poorly winding the strings rather than needing a locking tuner. YMMV