Carbon fiber air box kit Toyota GR Supra A90/BMW B58 The carbon fiber kit from DO88 replaces the original air filter box, beautifies the engine compartment and makes the intake more efficient for your B58. With this air filter box, airflow is improved with a larger diameter of 105mm at the inlet that tapers to fit directly onto the OEM turbo. Characteristics: Large 105mm (4.1") Air Filter. Washable and reusable for long life. Completely closed design that ensures a low intake temp. Increases airflow by 24% Improved throttle response and faster spool to the turbo. Compatible with multiple turbo upgrades. Fits bolt-on: Toyota GR Supra (A90 A91) B58 2020- BMW Z4 M40i (G29) 2018- Assembly instructions