Everything on this page follows from one fact about the instrument: a tres is three COURSES of two strings, and two of those courses are tuned in octaves. That is what makes a single-note figure sound like two instruments, and it is also why buying, stringing and setting up a tres are not the same jobs as they are on a guitar.
These are explainers, not a catalog. No prices, no brands, no gear reviews — this site has never played the instrument you are about to buy, and would not tell you it had. What it can do is tell you what to look at, in what order, and what each thing changes about the sound of a montuno.
Where to start
If you do not own one yet, start with your first tres: the neck and the nut decide more than the body does. If you own one and it sounds dull, start with strings and courses, because a dead octave string is the most common cause and the cheapest fix. If it sounds fine but plays badly, setup is the page — spacing, action and intonation, in that order.