They dont have to be black .A light gray works just fine.Doing this hobby can at times be fustrating,and by sitting there tring to scribe lines is not my idea of fun.I saw a beautiful converted 2 door to 4 police black and white at l.I.A.R.S. model show on long island this year and the builder used pinstripe for panel lines ,and it looked just great.Or the model companies can be nice and build more 4 doors.2days ago came back from toy fair in ny.I talk to these companies about more 4 doors and all they can do is submit the idea,but as you know it rarely goes far.the only one who does have a interest was Mr lowe from hawk lindberg.Now this is a guy who is a plus for the hobby and has interest in what you say.