I have these pipes (headpipe/silencers)...and it looks like I'm slower (got severely dusted by a heavily modded scrambler 400 in sand with the Graydon whereas we were equal on a hard packed gravel road with stock pipes) and louder compared to stock (right, the stock plumbing, with the spark arresters).

Where could I find info on this pipe?

Or anyone have personal experience...etc

I'm serious about this question...could they be less powerful and louder than stock? Could they dare to give lowend making you loose so much top end?