People ask if a $300 banjo can be improved or will it always be a $300 banjo, I've little experience on $300 Asian banjos but I did some alterations on a $375 Asian banjo that did a lot for it. The banjo was a Gold Tone MM-150 that I got below the normal asking price because it had been sold once and come back almost immediately due to a minor finish flaw and major inability to hold tuning. I think they sold for about $450 normally. I never checked. I knew why the banjo wouldn't hold tuning - the neck was loose, a problem common with Asian banjos. The guys in the guitar store had no idea about that - they could have kept their original sale if they had known to tighten up the neck to head connection.
At that time Gold Tone also had a $250 banjo - the CC100 (I think it is still in their catalog but the price has gone up). I probably should have bought that one but I really thought that I could get a Whyte Laydie sound out of the MM-150 with enough modifications. I was wrong. I improved it a lot, but it was no Whyte Laydie. For the records I've never heard an Asian banjo that sounds like a Whyte Laydie - but I haven't heard all the Asian banjos out there. My feeling is that the classic WL sound is only obtainable with a BIG pot - 11 13/16ths or 12 inches. The best way to do that is to find an old one or buy a Bill Rickard 12" pot and install your own neck.
BTW: The prices I quote here are circa 2003.
I started by removing the original tailpiece and tuners, tossing them into a box to re-install upon selling the banjo. A Kershner tailpiece I had around improved the sound immensely. The tuner change (I used a set of 5 Stars I also had around) went well although the 5 Stars went in pretty tight. I played this banjo for a couple years until I decided I had to have something better. It was pretty good for the money, but without those upgrades I wouldn't have had what I call a playable banjo.
The original tailpiece was pot metal poured into a mold. I've heard a lot of tales of them simply breaking under string tension, and can believe every one. As a side note I was going to put this tailpiece back on the MM-150 when I sold it, but I was so disappointed with the sound when I did, that I literally wouldn't have felt good passing the banjo on with that POS. Even if I am out of the business I feel I have to maintain my good reputation.
The tuners were typical Asian no-names and can be bought under the Golden Gate and other brand names. They start out okay but begin to disintegrate within a few months. I've been all too familiar with these tuners for decades and would never buy them.
My experience with Gotoh tuners was the same as with other Asian tuners but the current distributor claims they have reworked them and are now "the best". I tend to remember the sets we sold and had to take back when they broke down. The distributor at that time refused to accept them (although they did take the un-sold sets we returned). They said the sold sets were past the warrantee date. That distributor dropped them from his next catalog. Times change, but my memory doesn't. I will stick with 5 Stars.
If you are going to install a set of Gotohs in your banjo - you will usually have to modify the holes in the peghead (unless they are replacing some other tuners with the same diameter shafts. Gotohs (and Schallers) are a bit smaller than most - in my experience. I usually fixed this sort of mis-match with a thin curl planed from a rock maple board, although a bit of cardstock would probably do the job. The shim does not have to go all the way around the peg.
The 5th string peg in a Gotoh set has a killer spline that splits it's way into the neck wood of your banjo. I recommend filing this down until it is no bigger than the others. The normal splines on a Gotoh 5th string peg are quite enough to hold the tuner in place - in fact they are all on the big and scary end of the spectrum. I think the Gotoh makers are a bit paranoid about them turning in the hole.
The Gotoh 5th string tuner is geared at 18 to one. It is a guitar tuner welded to a splined peg. I dis-recommend it highly. Other 5th string pegs tend to be 8:1 which, although not the same as the long pegs is at least in the same ballpark. Some people feel the opposite about this and say they need the superfine tuning the higher gear affords them. I feel that if your pegs need higher gear to tune well, you need better pegs
Gotoh and Schaller also have the problem of coming with big showy Mother-Of-Toilet Seat buttons and no easy replacements. With 5 Star there are all sorts of slide on replacements including some real sharp looking black old timey buttons. It is a real pain modifying tuner buttons. I don't do it - period.
If you have a $300 banjo with guitar style tuners - keep them. The modification to take any brand of geared banjo tuners will cost you at least 50 dollars - plus the price of the tuners. You cannot recover any of this money when you sell the banjo. A used banjo is a used banjo and a used 300 doller banjo is probably going to go to someone who will have no appreciation of the "good" tuners you installed. He wants a used 300 dollah banjo and you'll be dimmed lucky to get $200 - in excellent shape.
If you are looking at a low priced banjo that normally comes with guitar tuners but can be "upgraded" to banjo tuners at the factory - don't do it. Not only have you paid extra for a modification that cannot be recovered when you sell to instrument, but the banjo tuners you will get in an Asian banjo are those same generic tuners I've been talking about.
The final modification was the set-up. I've been setting up openback banjos since the 1960s and have a pretty good sense of what each one needs.
I tightened the neck (loose in the store - the banjo had been returned because it was un-tunable) and zeroed out the co-rods on the MM-150 (one was too tight and the other dead loose when I got it). This alone probably did as much as anything to improve the playability. Most Asian banjos I see have the necks too loose, but this is not a "User" fix. Unless you have done this sort of thing before a banjo is probably not the place to start.
I also set the neck angle a degree or so further back than most people. I worked in a shop where the owner was into archtop guitars. I decided I liked the geometry better than on flattops. Most banjos are set-up like flattop guitars, I prefer to go with a bit of the archtop. a couple degrees more than normal keeps the action lower across the neck and allows for a higher bridge, giving more volume and a richer tone.
As I said above, a set-up is probably not a great idea for a home project unless you are experienced in doing some musical instrument repair work. I think most long time old time players eventually do their own set-ups but you have to "know" what you are looking for in the way of sound, and that takes experience. Leave the job to professionals if you have any doubts about your abilities - and perhaps even if you don't.