Re the Montesa's there is no doubt that Fuji's sounded like it had more bark but then again so did his 2 strokes.
The chief Montesa mechanic, (who was Dougie's mechanic a couple of years ago), told my father that the engines were indeed standard but no doubt the ingnition mapping / fuel injection was tweaked. He said the factory engines would be available half way through the indoors but they were very happy with the outdoor performance as already the riders are managing to do the same sections as they were on the factory 2 strokes.
PS.looking closeley at the bikes they all had factory suspension and other bits