Hello, I've been interested in learning to speedrun this game but currently I will only be able to play on an emulator. Is there a specific one I should/can use? Thank you

Only one that is currently allowed is PCSX2 with these versions: 1.4.0, 1.5.0 or 1.6.0.

You can find out all you need in the "Game Rules" part when you click on "View rules" button.

thank you!

one last question, Where is a good place to find the iso i should use

Since its pirating, I cannot link you. Try and ask the emulator runners in discord

Linking and sharing ISO is piracy, however if you have the PS2 disc and a disc drive on your PC, you can play the game directly by the disc by choosing Plugin in the CDVD menu. You can also rip the ISO using a program such as ImgBurn to create a .ISO file from disc.

Does anyone know if using RPCS3 (A PC Emulator) to Run is allowed?

It's not allowed right now, but we're currently in the middle of discussing the possibility to allow it for runs, for now it's a great way to practice the game(s). I'd suggest joining the discord server in case you haven't yet so you'll stay up to date with the current rules since we announce every change there. You can find the discord here https://discord.gg/pcFMc8xg (if that doesn't work for some reason, you can use the discord button here on this site)

update: the swag is happening by 1st may yahoo