Well, if you want the BASIC TOTO Drake with a GMAX for the cheapest. The model number is CST744S. For the Sanigloss (Better bowl rinse) is CST744SG. But if you have a round toilet, you can NOT get the Sanagloss model sadly. And if you need any parts, you can use the OFFICIAL TOTO Parts store, that is actually GENUINE parts used by TOTO in the factory. I recommend to try to avoid from buying Fluidmaster stuff for your TOTO. The TOTO/Korky parts give a much more reliable performance. TOTO Parts Store link https://totostore.us.com/ please feel free to ask me or any other members on here for help. Hopefully you will love your TOTO!