IIRC that was "designed" to help turbo spool and efficiency. Not sure it's even necessary with the tuning that's available now, but it might be interesting to see if it makes spool that much better still.
In your origonal post I see no link or picture so I am not positive what you are referring to.
I think you are talking about the woven exhaust wrap,comes in a roll 2" to 6" wide.
Have not used it on a 6.0 but have used it with so-so results on heavy equipment. They sell one type that uses a sheet rock mud like stuff that you coat it with after wraping, stay away from that stuff it produces fumes and after a short time it breaks up.
WARNING: Read the label carefully some of the stuff sold still contains asbestos.