I believe that the D Series and Roamer should be separate vehicles in the menu. Having them grouped together doesn't make any sense, since they are separate vehicles. Despite the fact that they share the same chassis, they both serve different purposes, handle differently, and are different classes of vehicles. Trying to customise the Roamer can be a pain, since all parts on the roamer start with either a "D Series-" or "Roamer-" prefix, and those prefixes always cover up the part name in the parts selector. Having them grouped together also (at least to me) makes the Roamer feel unfinished, almost as if the devs just never got around to separating the roamer parts from the D Series parts. Separating the two vehicles would also add another vehicle to the selector menu, making sure that screenshots of the vehicle selector menu are representative of the true number of different vehicles in game. I have some more arguments as to why they are different vehicles in this thread: http://www.beamng.com/threads/why-i...h-the-d-series-in-the-menu.16925/#post-265453
I would also like to see them separated into separate vehicles. No other car is grouped with another car. Even though the Roamer has the same chassis as the D15, I would not call them the same car as they are very different in both shape and performance.