Notes: If welded Assy, replace all Reqd parts.;w/Single Catalytic Converter; w/Cat Converter; Dual Outlet; If welded Assy, replace all Reqd parts; Optional; HD for 18239;w/Single Catalytic Converter; w/Cat Converter; Dual Outlet; If welded Assy, replace all Reqd parts.;w/Cat Converter; If welded Assy, replace all Reqd parts.