I found that I would put the body together first. And then paint it. But seeing I never built one where the sideS have to be glued to the middle piece. I didn’t know. If I did I could have finished the body seams a bit better. As far as the grill and such. I’m not that talented to change those dimesions. But you can. As long as you have fun in the building. That’s all that matters. :-)