FYI, the Gruppe M intake uses the left plastic wheel well as one of its sides. This means that if you were to open a hole there, it would suck in cold air (along with the water and mud). The brake duct is in close proximity as is the area between the brake duct and fog light (on the M-Tech bumper). K&N makes several custom fittings including a flange and tubing that can be bolted onto a modified grille.
The idea is to increase the intake of CLEAN cold air.