This issue has persisted since Forza Motorsport 3. The Advan RG-II wheels in Forza have an inaccurate model. The very shape and curvature of the spokes is very wrong. The overall quality of the wheels is also low, they seem lower poly than post-Xbox 360 wheels.
An accurate model of these wheels already exists in Forza, and can be found on the “HiCar” Donut Media 350Z. Despite the weird texture artifacts, they are much more accurate than the current model.
The deep dish variant of these wheels, Advan RG-D2, also has a more accurate model. As it should, because they were first added to Forza in Horizon 5
