Kit 20001 (the all-blue 1976 version) would be preferred, as it is "vintage," while kit 20053 (blue and white 1977 version) was a 2002 re-issue, with a few different parts in it. I think most of the changes were in the bodywork, so 20053 still contains the popular engine and suspension components, and it will probably work fine in a pinch. If there are specific parts you're concerend about, I have both kits and can compare.