The 350Z has very poor under-car airflow in the vicinity of the differential, thanks to its good from the factory aerodynamics. For this reason, the Z is very prone to overheating the differential, especially if a mechanical limited slip is used.
The Z1 Motorsports cover’s generous finning really helps keep the diff temps under control. Overheating of the diff can cause it to seize, suddenly locking up the rear wheels.
In this picture, you have a better view of the additional reinforcing ribs around the mounting stud boss. I feel that this is really going to prevent the kind of incident that took out my car.
These are the solid bushings that came with the kit. They are going to be a lifesaver since this was the failure point on my OEM setup.
In a case like what happened to my car, failure of the rubber mounts allowed a lot of free movement, which broke the mounting stud off my stock rear diff cover, putting a lot of extra force on the front mounts. This overworked them and allowed the diff to fly out of the car, breaking the driveshaft on the way out.