I have had the same experience.

When I first mounted my body, I expected it to be the same as the JC ones I had mounted previously, so I notched the front of the body to clear the bumper downtubes. Whoops, too low. But it made 'kiting' worse. A strategically placed piece of duct tape helped a bunch.

The next bodies I paint, I'm going to mount them first and leave maximum chin spoiler below the cut line.