Sorry for taking sooooo long. I finally got a chance to do some toying with the add-on disc package from White Bros. As I had posted before, the "stock" 8 discs including the quiet core registered 94-95 db at idle. Added two discs, 96-97 DB. Added two more solid 97. Once I get this tachometer project finished I'll be able to post some 50% throttle readings. All the previous readings were taken at 20" and 45 degrees from the exhaust outlet.

 

My dealer had a white bros. pipe sitting on the shelf so I almost bought it. Maybe next time. Good info you posted.