It may sound funny but the dash was one of the big selling points for me when looking at the Z's. There's nothing better than those curves on a nicely reupholstered dash. This was done by Dashboard Restorations in Brisbane and I highly recommend them.
I am most likely going to be using the seats from my 1974 260z (pictured) and recovering them with white leather trim. I was going to use a set of 300zx (Z32) seats but they don't fit in very easily. The width of the seat is fine but the rails on the 300zx sit up on the fire wall. Also the seat sits high as they are mounted to the floor in the 300's whereas the 260 has a bracket/mount to bolt onto.
The carpets I used for my white car are a piece kit and are honestly quite anoying. They move around alot even with button clips and custom stainless steel trim to hold them in.
For my good car I will be using a moulded carpet kit. A company I found on ebay (Auto Carpet Professionals) are selling moulded kits so I will probably be trying them when it comes to carpeting my project car.