I did some checking and your 1991 Nissan 300ZX uses an oil filter with 3/4"-16 threads with a 2-3/4 inch O-ring diameter. For that you can use Derale Thermostatic Sandwich Adapter Kit # D15730. view full answer...
For your 1991 Nissan 300ZX I recommend the Thule OutWay. What makes this rack far superior to the others is the attachment system. It uses only 2 retractable coated steel cables to attach to the vehicle rather than 6 nylon straps like other racks. This makes installation quick and easy and the cables also last longer.
The cables store inside the rack so there are no loose straps ends to flap around. The cables can also be locked into position to deter theft of the rack. And there is also... view full answer...
Yes, you are correct. If you used all 4 of the D-rings of the Brophy Tie Down Anchors # RR6K-4 you'd have a safe working load limit created by them of 8,000 lbs. This would be more than enough for your car that weighs 3,900 lbs. view full answer...
You're correct there is some drilling required to install the Curt hitch, part # C11703, on a 1995 Nissan 300ZX.
I've linked the installation details and attached a picture of them for you. The drilling is explained there. view full answer...