I was at Hangtown in '98. RC was absolutely flying on a KX125. He would probably have finished third in the 250 class on the 125, and Hangtown has lots of big uphills that need power.
When Stewart was on a KX125 he was doing things the top guys on big bikes were not. I've seen him tabletop not 2' from a jump to miss it, lap after lap.
I remember Joel Robert the same way. Absolutely the fastest guy around, faster than the open bikes on a 250.
David Bailey, Hannah, O'Mara, Ward, Johnson, McGrath, the list goes on and on.
There have been a lot of impressive riders through the years. Sucks that some of us hammer them for this or that, when none of us normal guys have a fraction of their bike control or determination.
When you come to a fork in the road, take the single track instead.