Have any of you used or know a friend who uses the New factory 4 from FMF. The anodized pipe looks sweet, but wow what a price tag. It does come with header and jet kit, but it's still expensive. https://www.fmfracing.com/products/catalog.aspx?CategoryID=38&ItemID=044073 What insert are you guys using for the stock pipe to lessen the noise after the stock insert has been removed? Thanks from a new member..