About the roadster parts; I'll give you the short version about my story. If you want the long one, I can send it to you by email as I think it's off topic here

During my restoration I worked with Nissan Belgium to get parts, with Nissan Motorsport USA and with most of the Datsun Roadster dealers in the USA. All the parts I couldn't get anymore through Nissan Europe (and only a handfull were still available) I ordered in the USA.
Due to shipping, and import taxes the price of the ordered parts became 3x expensier.
So restoring the roadster was a financial disaster.
Now that the car is nearly finished a discovered with the help from Nismo Japan, that all parts I ordered in the US are still available in JApan and even parts that are NLA in US are still available in JApan.
Long ago someone in the US and Europe decided to put all parts that are older then 20 years on a black list (NLA) to reduce the STOCK and COST. Parts with an NFS- not for sale- code were supposed to be special orders only. But poeple left and other came, and someone forgot to talk about special orders on NFS code. Still later NFS listed parts have even been removed from the importers database.
So you really need a good contact at a dealership in Japan to check with Nissan Motor Limited in Japan. Once I know that the part is available in Japan, I have enough in my hands to ask Nissan Europe to get the part as special order from Japan.

So if you cold help me with my parts, it would be a good resource for you and your roadster project too.