From what I can see, downforce is broken for high downforce cars spawned into story mode. The performance of cars like the Krieger and Emerus is terrible when I spawn them into SP. Is this a known issue?

Specifically, do the items in vehiclelayouts.meta need to be referenced somewhere to be used? I ask because most add-on cars don't use their own vehiclelayouts.meta and the ones that have it only seem to use one or two items or none at all. I have one nice add-on car that has an elaborate vehiclelayouts.meta, but all of the name lines reference a different car mod from the same author. I'm guessing those items would be useable if they were referenced in vehicles.meta, but none of them are. Just as an experiment, I deleted all of the items in that vehiclelayouts.meta and as far as I could tell, the car worked fine without it. So I'm guessing that anything that isn't referenced in vehicles.meta is just extra junk left over from a copy paste. Is that right, or is there some other way the game uses vehiclelayouts.meta that I'm missing?