If you decide to repack it, my vote would be for stainless steel wire wool. I've hacked a Yamaha R1 titanium can into a silencer for my clubbie - it's like a big hotdog.
I initially packed it with fibreglass but it only lasted a week or two. I then wrapped the central perf tube with fine SS mesh, and packed it with SS wool - both of which should be available at any decent muffler shop. It's all been in place for about 4-5 years now without any problem.
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