my 1st suggestion, is manual setup what color i like for a car just a checkbox where i can choose basic colors red blue green so i can choose 1 to all
But the main topic for that suggestion are more than cars here are some pictures
all that different special cars and trucks will be more interesting for me as example an resqure truck needs medical supply, a cap/taxi need extra electroic equipment that will be awsome to have in the game, and of course an extra challenge becouse extra mashineries, i realy want to build green firetrucks ;D