BMW X Series X6 Series Transfer Case Bush Insert (Motorsport) - PFF5-1428BLK PFF5-1428BLK Transfer Case Bush Insert (Motorsport) is made from our stiffest 95A Black Series material for Motorsport use, providing a no-compromise performance option for track-focused builds. An increase in NVH, usually at idle, should be expected when stiffening the mount between the transmission and chassis. The harder the material, the greater the NVH transmitted. - NOTE: Price is for CAR KIT, NOT per bush… Powerflex price their bushes individually, but we have combined the quantities to make it simple!