Good advice from JS. I had an Epi Sheraton. I to had heard that it would improve the tone and sustain. It cost me 60 bucks including the bone nut.
I could not hear any difference! Nor could I see any.
I would only replace a nut if the strings are sloppy in the grooves. The nut may not be cut deep enough and the string will sit too high on the nut. This would affect the set up to a certain degree. On a 45 dollar guitar I would not worry about that. The upgrades you are doing on the electronics will make a huge difference.
As a side note, my guitar tech will adjust the nut during a set up. He finds it makes it much easier to get a really good low action, even if it's plastic.
The Blues is alright!
Guitars: 1968 Gibson SG, 2005 Gibson SG Standard, 2006 Gibson LP Classic Gold top, 2004 Epiphone Elitist LP Custom, 1996 Gibson Les Paul Standard. 2001 Epiphone Sheraton II, 2007 Epiphone G400.
Fender Strats: 1996 Fender 68 Reissue CIJ, 2008 Squier CV 50s, 2009 Squier CV 50s Tele Butterescotch Blonde
Amps: Blues Junior Special edition Jensen in Brown Tolex with Wheat front, 65 Deluxe Reverb reissue,1970 Sonax reverb by Traynor, Avatar Custom 2/12 Cabinet with Eminence Legend V1216 speakers,
2008 DSL100 Marshall Amp , Fender Super Champ XD,Fender Vibro Champ XD
Effects and Pedals: Fulltone Fulldrive II, Fulltone OCD, Fulltone Mini Deja Vibe, Fulltone Fat Boost, Dunlop Crybaby Wah, Boss DS1, Boss DD20 Giga Delay, Boss TU2 tuner, Boss BD2, Ibanez TS9 Tube screamer, Zoom 505. Radial tonebone hot british.