[gsxrken]

Could be any of those things you listed. The only parts I’d order before running all sorts of diagnostics would be a fuel filter, cap, rotor, and properly gapped spark plugs. Those are cheap and never really a waste to do. After that you‘ll need to start troubleshooting- parts are too expensive to spray and pray with.

PS- Do you have a boost gauge or wideband AFR meter? Two relatively minor expenses that might save you thousands and help diagnose your issue as well.