random misfire 03 supercharged 3.3L manual

Besides the things you mentioned, I’ve seen:

clogged fuel filter
Fuel sending unit corrosion
Blown out supercharger gasket(this should have been replaced when the knocking sensor was replaced)
Supercharger bypass valve leak
Injectors
Clogged converters
Fuel pressure regulator
Water in fuel

This is why the service manual calls the P0300 “Multiple cylinder misfire” and not “Random cylinder misfire”. There’s usually nothing random about it