Subject line is the request. Requesting conversion from replacement to add-on of Mazda RX-7 FB3 and Renault Fuego.
Fuego, last touched in 2015: https://www.gta5-mods.com/vehicles/1980-renault-fuego-tunable
RX-7 FB, last touched in 2016: https://www.gta5-mods.com/vehicles/mazda-rx-7-fb3s
These modders aren't coming back. It'd be nice to update these to add-on vehicles. They even have some tunables. They are the only examples of these two cars.