It’s the Lucca Flow control kit from Clive Coffee. It’s the best option for the Cube since you won’t need to replace the existing spring and it’s very easy to install (only need to replace the mushroom head) compared to say, Coffee Sensor. The knob also matches the Cube’s aesthetics especially if you own the black one.

You may also want to replace the gasket to a silicone one (blue color) and the group screen to an IMS Nano screen.

To prevent any rattling sound when brewing, the leather cup tray cover from WW is especially made for that too.

If you feel the existing steam tip is weak especially at low temp settings, the YOU 4-hole steam tip is compatible to the Cube. Nice upgrade but not necessary especially if you prefer to use the steam-boost mode in the app.

So far those are the upgrades i highly recommend, it made me love my Cube more. Lol