Depending on how the panels and mesh work, it would be cool for lower quality bodies to have slightly different angles between panels (alpha map? Sorry I’m no game developer!) so that the light shining off adjacent panels suggests they’re not perfectly aligned.
Panel gap size and consistency could also vary in accordance with this, and depending on body panel material as well (so a fibreglass panel construction would show more variance and wonky-ness until you put quality up +6 at least, but handmade aluminium looks great at 0 or +1) to reflect the desirability attribute.
Quality of paintwork and overall refraction index could demonstrate this as well, almost like the slider on Kee engine colour selection.