Genuine BMW Wind Deflector Side Section. The Genuine BMW Wind Deflector Side Section (54347457891) is a precise replacement part for the wind protection system on the current generation BMW Z4. This side component is integral to the wind deflector assembly located between the roll-over hoops. It helps secure the mesh screen and ensures that airflow is correctly diverted away from the cabin, reducing turbulence and noise during top-down driving at higher speeds. Z4 G29 (10/2017 – 03/2025). ? Is this the correct side for your repair? Wind deflector components are often side-specific Left vs. To ensure this part number corresponds to the specific side of your vehicle that needs repair, please message us with your 17-digit VIN. We will confirm the fitment against the BMW Electronic Parts Catalogue (EPC) to ensure a first-time fix. Why Choose Genuine BMW? Perfect Alignment: Ensures the wind deflector sits flush against the roll-over hoops without rattling. Acoustic Integrity: Maintains the original factory aerodynamics for a quiet cabin experience.