The sprockets come in three parts, outer, middle, and inner. It is very difficult to get the outer ring (right) off the massive sprue without it breaking into tiny pieces.
The instructions don't tell you that the inner and outer rings can be lined-up to make the lightening holes. A lot of trial and error is needed to get the holes to line up!
The plastic in this kit is very soft, scratches (and sands) easily and reacts with thinner, especially lacquer thinner which melts and distorts the surface.