Too many versions... AC does not have a particularly version-friendly design, when it comes to the cars. Maintenance becomes a headache.
Wouldn't two separate cars: NA1 and NA2 make sense with sub-cars (?) for each version?
It should make each easier to manage?
Like so you have
Honda
-NA1
NA1 NSX R
-NA2
NA2 NSX Whatever
Then the same for Acura, Obviously you have done a great job and it may be a lot of work so whatever, but if you already have the physics etc done.