The GKTECH Polyurethane differential bushings are a direct replacement of the standard items and ensure that movement of the diff is kept to a minimum within the subframe which is quite common under hard driving conditions. - Polyurethane 80sHA construction - Available to order as front, rear or front and rear kit   Front, rear or front and rear? Front only: The front differential bushings are to be used when installing an S14/S15/R33/R34 differential in an S13/R32 subframe. The S14/S15/R33/R34 differentials have bushings on both the front and rear of the differential whereas the S13/R32 differentials do not. You use the original rear differential cover and then to get the front of the differential positioned correctly and then these bushes are to be installed. NOTE: Longer front mount bolts are required when installing an S14/S15/R33/R34 differential in an S13/R32 subframe (20mm longer = 80mm thread length). Nissan OEM part number is 55424-33P00 Rear only: Not very common but if you're running an S13/R32 differential in an R200 subframe (2 bolt cover) you will only need the rear bushings as the front of the differential is already solid mounted. Front and rear: All those non conversion 2 bolt cover cars. eg. S14, S15, R33, R34, C33, C34, C35 and Z32 We also offer a super handy diff bush removal/installation tool, more information can be seen here - https://us.gktech.com/s14-240sx-r33-skyline-diff-bush-removal-tool   Vehicle Compatibility: - Nissan S13 240sx - Nissan S13 Silvia - Nissan S14 240SX - Nissan S15 Silvia - Nissan Skyline R32 GTS-T - Nissan Skyline R32 GTS-4 - Nissan Skyline R32 GTR - Nissan Skyline R33 GTS-T - Nissan Skyline R33 GTR - Nissan Skyline R34 GTT - Nissan Skyline R34 GTR - Nissan C33 - Nissan C34 - Nissan C35 - Nissan A31 Cefiro - Nissan Z32 300zx (Non Turbo)