Direct replacement of the OEM parts. Best choise would be resing printing the parts in 0.05mm layers, but can be printed in FFM with nozzles of 0.4mm, 0.35mm, 0.3mm and layer height. Infill 100%.
Please keep in mind that the mouthpiece has to be temperature tolerant, so best printed with special engineering resin, or PETG, PA. Avoid normal resins, PLA, ABS