I replaced plastic with bone on my old Fender acoustic. Its a pretty old guitar, about 30 years and needed an update. Good guitar, solid woods, but nothing near an Avalon. The work itself is not a huge deal, the old nut popped off easily, and the saddle just slides out. The big thing is getting them sized properly. I ordered them from a guy in Tennessee. Had to send him the old parts, and he copied them. I did the replacement. The saddle just slid in. The nut needs a dab of glue (and just a dab...no more!) to hold it in place. Clamp it, let it set, and you have it. Of course, I'm no luthier, so I'm sure the guys at Avalon will be much more precise. Plus, if you have an Avalon grade guitar, let the pros work on it. You mess up and it will cost you much, much more later. Anyway, mine seemed to turn out okay and plays well. As far as any sound change, I wouldnt say it was drastic, but my ears are getting old.