I have a Comp Werkes pipe on my bike too, and I've noticed that it needs repacked fairly often. I've had my bike for two years now, and I've had to repack it three times. I used fiberglass insulation the first two times (once right after I bought the bike and once after a seaon of riding), but the last time I switched to stainless steel wool to hopefully make it last a little longer. I can tell when it's starting to burn out because it gets "boomy" inside my helmet. You might want to check that too, along with the db killer insert.
Here's the stainless wool I used, 1lb is enough to repack twice -
Link to Amazon. You'll also need pop rivets, I think they're 3/16"
