Thanks for the feedback!
Silly me, forgetting the mirrors!
I'll upload a revised version soon after I fix said issues. I'll see if I can turn it into a decent looking convertible and a hatchback, both would be cool additions. A version with more modern bumpers might also be a good idea, should make the body suitable for 1980s and early 90s as well.
About the 90s sedan, it's actually sort of ready and usable in game, as well as its coupe version. There is a stamping issue with it, though. When stamping a grille or a vent over the seams, parts of the seam start acting up near the edges of the fixture.
Like so:
All the materials are assigned correctly in the .lua file. The culprit may be in the UV mapping/unwrapping, but I've tried redoing it several times with no success.
Haven't observed anything like this with other bodies, be them vanilla or mods; so I know I must be doing something wrong.
There's also a slight issue with front wheels offsetting strangely when finishing the chassis part (but only after having morphed the body in a certain way before), but I figure that's not such a big issue.