I say fiction. I laugh when people say only elite pro riders, or 1% can use the full potential of a 450. Nonsense. Torque gives you acceleration, the 450 has loads of it and I use it! Sandy, deep conditions and jumps out of corners I’m stretching the cable on several sections and my dry weight is only 185. The “experts” like Matthes are spreading this myth that 450’s are too powerful. Stop it.
Having said all that for indoors is a 450 necessary? Of course not, and the racing would be just as good on a 350...still huck quads. And I say just as good, NOT better on a smaller cc machine. Is 250F racing better than 450F? IMO it’s not about the machine size at all.