Well first of all, which particular vehicle add-on(s) within this resource are you referring to?
“Missing thing?” @Crutchie asked about the texture dictionary files’ sizes beforehand.
You should ensure that the vehicle add-ons’ texture dictionary files (.ytd) do not exceed 16MB, as this is the imposed size limitation for streaming vehicle textures themselves. If the texture dictionary files do exceed this limit, you’ll be needing to split them in order to stream them.