Re: Bell Brass/Titanium bass bridge
I wouldn't do the nut. If you want it to match the bridge for aesthetic purposes, fine, but other than that, I wouldn't. I want the string to slide easily through the nut grooves, so I want the nut to be made of a material which facilitates that, like TUSQ. I remember 35 years ago when getting a brass nut was a bass player fad, and the rationale for it was better sustain. Through my own experience, I have never noticed a reduced sustain because of a non-metal nut. Besides, how often do we actually play open strings, and how long do we really need to sustain when we do? I usually have to mute the string at some point, if I'm not playing another note right away.
About the bridge, I say why not? I think it would be a fun learning experience -- unless you are paying someone to do it, in which case it's money out and not much experience, and I wouldn't recommend it. One exception -- if you really like the Badass III bridge but want to tweak it a bit, doing this would allow you to modify it however you want, and not ruin the resale value of your original Badass III.
To answer your question, it's not too much hassle if you view it as a project. If you don't look at it that way, and you are just trying to get a better bridge than the Badass III, then I'd recommend just getting another bridge. Personally, I'm not a big fan of the Badass -- I put one on a bass 35 years ago, and it was ok, but IMO there are a lot better options available today.