The only upgrade you really need is to have the appropriate mounting rigidity for the alternator, large enough wire between the battery and alternator output, with appropriate fuse/ breaker protection. And make certain that the VR (if external) is actually sensing right at battery voltage so it won't over charge
And of course the ground path also needs to be in good shape. On many systems this is already taken care of because the alternator is grounded to the engine, and the engine grounded by the main cable to the battery. BUT SOME modern alternators have a separate ground connection. So in that case, make sure it's in good shape and large enough
Yet another issue is whether or not you are using a "one wire" because those sense battery voltage through the charge/ output wire. This means that wire must be MUCH larger so that there is no voltage drop.
