messing around now.
if you really want to achieve the cheapest possible build, get the sport with hard top. sand down the hard top, it is white underneath, the same white you see inside it. It's plastic. Roll up your own sleeves, and put some elbow grease into it and sand off the textured black outer coat, then clear coat the raw white plastic, and you have your white hard top. And follow through with your original idea ala Porsche to paint the textured fender flares white. Cost you some effort on your part and you got what you seek.