i have a friend.. well more like, acquaintance lol anyawy he has an 04 z400 piped and my warrior chews it up an spits it out with ease, then again.. that is through really tight trails lol hes an ok rider but with a better driver i would have a hard time beating it, and the closest thing to a drag race was on a long wide trail from dead stop to about 4th gear, it was a pretty close race, never raced a 400ex tho.. just a 300ex