Picked up my Big Gun race series full system at MotoWorld (I'm fortunate to live kinda close to them and Moto-man)and they said the K&N kit is just a couple of weeks away from delivery. Hope they're not just jerking our chain. My Big Gun Is the new build and has mounts for the stock shield, something I have'nt seen on any pictures. I can get the quiet core and the spark arrestor works on both setups. Just what I was looking for, some adjustment from loud to somewhat quiet and still make the carp cops (DNR) happy (maybe). I can't believe different pipes can make much H.P. change. The race series is a straight through system. I'm sure the jetting and airbox mods are the biggest factors.