You can just barely see the edge of them but they are the u-shaped brackets that slip under the top exhaust clamp and also slide into the bulkhead rubber grommet bracket above the muffler. Pypes sells the brackets. I think they are an extra cost items not included in the kit. (of course)
Here's the old video of the sound:
https://youtu.be/ptAubfuN8N4
and the installation:
https://www.youtube.com/watch?v=3XsgWVUQ48s