when I was a kid I liked Ed Roth's work. not that this is it. Just made me like cartoony vehicles.
I made the general shape in Blender as it's really quick to to model it. I then imported it into Moi and I add and subtract with boolean operations. most indents are trimmed, offset, and then blended. it's all pretty straight forward. what's nice with moi is I can add style colors and they import into blender as separate materials.