Actually, I race my dads STOCK predator 500 06' up comp all the time, the only thing not stock is the suspension, and I usually beat anything from pumped up yfz 450's to ds 650's to some raptor 660's.
The only thing I couldnt really beat was a ltr-450. it had EVERYTHING you can possibly do to it,
i would either be in front of him, or be a bike length behind him,
but then he put the straight razor paddles on, and i couldnt touch him.