George is correct about the hood. It's needed for the earlier versions which don't have the updated sensors. You should ba able to tell if your Cortex has the new sensors by looking at the edge of the circuit board. The newer versions will have copper etch saying bavarianDemon on the edge of the circuit board just in from of where the wiring loom plugs in. It can be difficult to see as the space between the plastic case and the connectors is very small but if you shine a flashlight down there and look very carefully you should be able to see it. If you don't have the latest version you will need to use the hush kit.