I know that this isn’t an IRL brand but I think I can speak for everyone when I say that we’ve seen enough of the universal spoiler that Forza has. Here’s what I propose: letting us have the option to make our own spoiler. The default template can be the previously mentioned spoiler but we get full creative freedom on how we want to customize the rear aero. Hopefully this happens one day.
Gran Turismo 6 had a system like what you’re describing. I never had the chance to personally play the game, but I was very interested in some of the customization features it offered.
It let you build your own spoiler using a combination of existing parts.
Edit: As far it not connecting to a irl brand; Forza brand parts are already well established within the games. There are several cars that have Forza brand widebodies that don’t 100% match a real world equivalent. It would be great to see the game expand its customization by adding a bunch of Forza brand parts that can be equipped on most cars without worrying about licensing or some other limiting factor.
Forza’s game engine would explode if you did as little as replaced a model, let alone allowed for in-game modification or adjustment of any 3D models. I’m still all for it though