I'm amazed to find that some people are naive enough to still believe that any GT winner since 1990 was clean!! Prior to the 1980s, abuse was mainly confined to the use of stimulants, but with the availability of steroids and more recently EPO and other synthetic hormones, I doubt there's anyone who has been successful without. You only have to look at the changes in style of racing to see it happening - improvements in average speeds cannot just to attributed to passion or effort - regardlesss of how idealistic that dream would seem.