FYI, you don't need anything except o2 plugs to run 07+ Vance and Hines Big Shot Duals on an 04. I got a great deal on ebay for some 07+ pipes, so before I bought I called V&H to check on fitment. They sold me $70 worth of brackets they said I needed. Well, the brackets were all the same as what came in the box. You will have to reuse the clamp that is on the tranny mount or by an extra T-clamp to install it like the 06 and down instructions say. Just thought I'd share for people wondering what the difference is. The fitment is great, no install issues at all, no leaks, and the sound is incredible.