This is a an almost complete transmission mount replacement for the 300ZX/Z31, it is compatible with the Nissan FS5R30A and FS5W71C 5-speed transmissions, though it is not verified to work with the Borg-Warner T-5 from early model turbo cars. Only the formed steel bracket from the original mount (that part attaches to the body) is retained, everything above including the dumbbell and the upper C-shaped isolator is discarded. Weighing in at only 890 grams, this kit will also save quite a significant amount of weight, which will also make life easier when doing maintenance on or around the transmission itself.
The two shims provided set the transmission and driveline angle approximately to your desired position. Normally, only one shim is needed, but any change to engine mount height or subframe bushing substitutions could affect how many shims are ideal. Washers can be stacked between and above the shims for additional height, or as a thinner substitute for a shim. If in doubt, consult a driveline specialist about the best setup for your vehicle.
The main block has slotted upper holes to accommodate some misalignment between chassis mounting, the carriage bolts supplied should be able to slide around 4-5mm. It is possible to reuse the original T-head studs hooked into the transmission with the mount, but this would make it difficult to benefit from the slotting, as the nuts have to be tightened from underneath, possible requiring removal and re-installation several times.
Since one layer of isolation is removed, there may be a slight increase in road or transmission noise, but the bushings are relatively soft, so this should be minimal. Conversely, even though the bushings are soft, removal of the upper isolator will in fact limit movement to a greater degree, the tail end of the transmission will be unable to flop around or attempt to tilt as it could with the original rubber bushings and rubber engine mounts. Torn mounts should be a thing of the past.