Here are a couple of pics of it being stripped down. This particular one was blown, so it'll be getting a new sleeve.
There's not much to them really!
Also, as per Flip's ebay link, you'll want 400mm wide material for these exhausts by the looks of it. This will give some extra to trim off and ensure ifs fully packed. Flip, do you know if one or two 1m lengths is required for both exhausts?