This is better explained by BeamNG themselves—
The Gavril Roamer is a full-size SUV manufactured by Gavril from 1992 to 1999. It shares its chassis, suspension, and engine options with the Gavril D-Series.
Oh yeah, and it has a full interior and engine.
Interior
Wheel
Colour
Tyre
Colour - Bottom
Wheels
All cars have these wheel options and all of them come with the tyres Rendered. Other bigger vehicles have only one option, which are the ones rendered on the vehicle. Some wheels in certain rare colours may cost more to get, watch out for that, though I marked all wheel colours that were expensive as so. Car colours (interiors and bodies) can also be expensive, if you choose a rare colour such as pink. I mostly try to keep car costs down, but sometimes that is impossible!