OH!, I'm was condsidering modelling it the way you said. BUt what I did was built the body , so all the metal parts as one object. And then I'm going on top and removing/ editing to add the other details. Its a bit more work, but its wayyy too hard for me to work with piece by piece
. (but I'm only working on half of the car, the other side is mirrored)
and wow, I want to see the city you're making. I tried making one too, but my buildings are just extruded blocks, not very interesting