Windigo,
You could also check on
www.sporttwin.com. That is pretty much all buell riders over there, and a lot of very knowlegable folks on this topic.
From what I have heard, they are great pipes. It seems that the drummer differs from say a D&D, or the race kit pipe by where it puts the power. I think the drummer may make the most power down low in the rpm range rather then up high, but I could be wrong.
Oh.. and they sound b-e-a-utiful, IMHO.
Hope that helps a little.
Russ