I put in a good weekend or racing and riding with my new Thunder Alley Pipe installed on my '06 450. I have to say that I am very happy with my purchase. I didn't expect anything less, because I have been happy with these pipes in the past. Just as I hoped, it added a blast to the lowend. I think the '06 is a little soft down low with the stock pipe. The bike now has a ton of smooth power from crack of the throttle to the top. To me, this makes the bike easier to ride. More power down low = less downshifting in a corner. Best of all, my exhaust does not reach to the end of the fender now. At 250 bucks, this pipe is a real bargain in a world of 600 dollar plus exhaust systems.