After that the devs have seen my thread about colored rollcages.... http://www.beamng.com/threads/colored-roll-cages.24818/ ...I would suggest the possibility of changing color of the rims. Yes I know there are some black and white rims but they are not fully colorable.
This would be pretty cool to see. I could finally satisfy my tacky tastes with a bright blue covet on pink steelies.
Both with different levels of chrominess? well you can kinda already do that... not like we dont have chrome wheels.