I would say get rid of the black between the spokes and the brake discs. so you cna see the ground threw the weels thn it will look more realistic...
adn play with to colour saturation / levels of the rim paint "blacken" it up som more .!
only critisise cause thats what I do all day work in multimedia look at ALOT of pics..and do ALOT of photoshop...
and one more thing. loose the lense flares.... or change there colour.. look kinda gay.