Lance Armstrong: If Guilty of Doping, What Would Become of His Legacy?

 

New doping allegations have come out after Sports Illustrated came out yesterday, in which two SI reporters reviewed hundreds of pages of documents and interviewed dozens of subjects in Europe, New Zealand, and the U.S.
The revelations can be found here.
It begs the question, what would become of Armstrong's legacy if he was proven guilty of using performance-enhancing drugs?
Would it slightly fall, or would it collapse?
Armstrong has been unmatched throughout his career. Did he do this naturally or was he unmatched based on illegal means?
How would you view Armstrong if he was proven guilty of doping?