I managed to get the kidneys off using my wife's hair drier. I plastidipped both parts matte black for a more serious appearance.
@GI3L: I would not leave them off. There are "slots" with holes and nooks that don't look good neither aerodynamic. The holes are through the underside of the hood...
Hi, I tried to do the same thing as you. However, I do not dare using force when "un-adhering" the kidneys. Do you have any trick? All four screws on each kidney is of course removed.