One person who helped us learn about the similarities between the R31 and F31 was Fergy from Velocity.is.faster (website/team). Scourge (Thomas) knew him and mentioned him many times. Fer lived in Japan and had an R31 Skyline for many years.
When he looked at the F31, he said they are pretty much the same and similar.
When he moved to Hawaii, he brought many of his R31 skyline parts and put them in an M30.
Fergy’s knowledge helped spark some interest in to what would work on the F31 from an R31.