Consensus on the board seems to lean towards PAMCO. Guy has good service and a good product and doesn't have suspect quality control issues that crops up here and there with dyna stuff
Also, there isn't stages, that's a ricer thing. Do you mean you want to bump up the main jets, pilot jets, tweak your needle clip position? If so search there are good guidelines. Tell us the setup you intend on running and we can point you in a direction. Tuning is the name of the game tho you don't have a luxury of little reflashes that someone else did.
You could try jets r us or post a want ad on the board. If you aren't really doing any mods you don't have to change anything. For a free flowing exhaust, k&n drop in filter and hotter ignition most guys hit 125 mainjet max and maybe bump up a pilot jet one size, middle clip position on the needle jet.
Stuff like that^^^ you can look up. Search the left toolbar, there is literally 100's of posts about what you are asking that is why most don't rly answer