a sunburst pickup? LOL. Now we need some sort of a fastback and a liftback bonnet --- Post updated --- Oh, so you didn't got the model yet? very good experiment!
For the initial release there will not be any alternative bodystyles but I did intend to eventually make a ute body too, since the turbo sticking out the bonnet was inspired by the Subarute after all. The boxer (at least my version) does not fit in the regular Sunburst chassis though so any currently available alternative bodystyles will not be compatible with the boxer.
It will be in the vehicle selector with the Sunburst, but it will have a separate "body" and certain parts (hood, front suspension, some other things) will have their own "boxer" versions so they will not be compatible with other mods either. It's not ideal but to me this seems like the "best" compromise.