I don't see the need to replace the ecu with silicone, if when you open it it does not bend or ruin too much of the lid you can close, so without silicon, remember that in each case, the control unit is not hermetically sealed, if you see the black cap which is on the ecu the same and open to make antrare air, so it is not watertight, as far as the wire boot external be honest I find it ugly and the price now there are also new tools that read and write to the ecu at the desk without opening them in bench mode.