Boy am I glad to find this site! Been lurking around for awhile and now I need something that I did not find in search mode. Short story, I have a 426 with a full White Bros E Series system. I used to ride harescrambles and sound was not an issue. Now trail riding with buddies and they hate me. I decided to try the quiet core insert. No dice, different sound, but not quieter. I am running 10 disks. Any more the bike is obnoxious, any less the bike runs poorly. Being the smart guy that I am (being a cheapskate has nothing to do with it). I ordered a Yosh slip on from an Ebay seller that is advertised as a 96db unit. Guess what? It don't fit my WB head pipe. Now I feel stupid. Do I try to send it back and get the full system or try to find a stock head pipe to work with the slip on I already have? I would love to find a stock head pipe to fit the new Yosh slip on so I don't have to buy a new system, ship the other one back, worry about a credit, and so on.... So, anybody got one? Price?