BMW 4 Series F32, F33, F36, F82, F83 (2013 - 2020) Rear Diff Front Mounting Bush - PFR5-4025 PFR5-4025 is a replacement bush that includes aluminium sleeves with built-in support to increase control of rear diff movement and replaces all four bushes in the original rear diff front mounting bracket. - NOTE: Price is for CAR KIT, NOT per bush… Powerflex price their bushes individually, but we have combined the quantities to make it simple!