The CLA 250 has a 0.28 Cd, not 0.23. The CLA 180 stripper on skinny tires has the 0.23 Cd.
Mercedes-Benz Deutschland - Technische Daten - Modelle
CLA 250: 0,28
CLA 180: 0,23
When viewing the link, make sure to select CLA 250 as the model on the left side (the default is the diesel, which has a 0.24 Cd).