Its not at all difficult to remove the OE diffuser, there are several screws along the bottom, and the clips come out with modest force. Just be careful about how you pull on the clips, the bumper flexes with it. Take your time and its simple. There are multiple high quality cf diffusers out there.
E88 FBO N54 Alpinweiss/Coral Red/Meisterschaft Race/Berk Resonated/Macht Schnell 3"/ER CP/Synapse/VRSF FMIC/BMS DCI/BMS Thermostat Delete/Rob Beck PCV/BMS OCC/Cobb 4.02/Alpina TCU Flash/Icarbon/3D Design/Cyba