If anyone's interested in a new pipe for thier WR/YZ, it may be worth your while to check out Thunder Alley's stuff. Bob at Thunder Alley makes these by hand, order by order, and also suppled me with suggestions for jetting. Bob sells them for $250 and I ordered mine with the optional spark arrestor for an extra 45. I heard alot about this pipe and how well it works on the YZ side of TT and they ended up selling me on the idea. I just got mine today and just couldn't wait to get it on and ride. First off, this is not the pipe for the guy who's looking for a fancy looking, pretty boy, titanium/stainless steel junkie worried about all the fluff. This is hand made to perform and not to look pretty. However, you can have them ceramic coated if you're worried about looks and maintanance. The pipe is sturdy though and looks to be really strong. Unlike the FMF-Q pipe or White Brother E pipes. They just seam a bit cheap to me. The fit was also perfect. I didn't have to push, pull, twist, or fuss with anything to get it to fit. Just unbolt the old stocker and bolt up the T/A. Couldn't have been easier! Then I started it. Well, if your worried about noise, it might be a bit loud for you. I'm not 100% sure, but I'll bet it is at least a db or two louder than the uncorked stocker. Supposed to be a bit quieter than the T/A without the spark arrestor, but I don't know how much. Can't imagine it's that much quieter. How'd it ride? All I can say is "OH MY GOD!" This thing absolutely makes my bike rip. The power comes on right off idle and pulls nearly all the way to the top. It does flatten off a bit on top, but getting there is a major rush. The place I noticed the biggest change was coming out of turns. Just lean the bike over and grab the throttle. It'll launch you right out of the turn and throw you to the next one. I don't think I ever had to brake so hard. At the end of even a small straight the bike is just screaming. Then I headed out to try a top speed run. I felt like the bike pulled really hard all the way until I got about 1/2 way through 5th. Then it seemed to flatten out a bit, at first. When I let off I realized I was going faster than I've every had this bike up to. Just wish I had a spedometer or GPS so I could tell how fast I was going. Unfortunately I didn't have any of my riding buds with me as a gauge, but I think I was going faster than ever. This was the first time I've experience head shake with this bike, which tells me I had to be screamin'. If your looking for performance out of your bike, you owe it to yourself to check this one out. I cannot believe the difference in low and mid performance. I love this pipe. Didn't even need to change anything on the jetting. I love this pipe. Just bolt it up and ride. Did I mention that I love this pipe? Well, I love this pipe.