Anyone used these? White Brothers puts them out, and it is a machined steel collar that fits in the headpipe next to the exhaust port. It's like a stepped headpipe, and is supposed to improve throttle response and low-end power. Alba also uses them on their kitted Warriors. For those of you with experience, do they do as advertised? Does it adversly effect top end horsepower? I need a bit more low-end on my modified Warrior.

 

I installed one but did it at the same time that I installed a White Bros E-series slip on. Therefore, it was hard to tell if the stuffer actually did anything in addition or differently than the pipe. Top end does not appear to be degraded (I took it to the dunes over new years as a back-up bike and ended up riding it quite a bit - it performed well). I can say that the pipe/stuffer combo is a nice improvement. The only thing I dont like about the WB pipe is that it turns the cooler black from the heat/exhaust coming out the sides. Worse yet, it might be making the beer warmer by a couple degrees on that side - cant have that.

 

helped just a tad on my wolverine, it didn't hurt topend any.