Re-packing mufflers

The 4-2 Kerker exhaust on the VF500F is LOUD!! I pulled one of the baffles back a couple of inches thinking maybe the packing had blown out, but there's still packing in there. I didn't remove it completely, but it seems to be cloth or fiberglass of some kind, not steel wool.

I read that if there's TOO much packing it can actually make it louder. Can the packing degrade or get sooty and carboned up over time and lose it's effectiveness?
If I repack these, what's a good material for a nice, meaty, mellow sound? This thing is just plain obnoxious the way it is currently.

If your packing gets coked up with soot, or hardened, it could certainly affect your sound.

I just did the muffler on my Wolf 4-1 pipe using Roxul rock wool insulation (R 13.5 if it makes a difference lol). It's non-woven (less likely to get stringy and flake apart), fireproof (very handy in a high-heat application; won't burn out), and I happened to have a bundle left over from a reno project a few years ago. Just wrap/pack it around the muffler core semi-tightly until it's about 1/2" thicker than the muffler can. Use masking tape or hockey tape to secure the packing and shrink it small enough to fit back inside its home. Reinstall and enjoy!

It killed the hornets that swam in my head every time I started the bike, removed the ringing in my ears at 4500rpm. As a plus, the bike seems faster now (probably because it doesn't hurt to run at normal cruising revs)!

You can't pack fiberglass tight enough by hand for it to be "too much". Basalt (rock wool) attenuates better than fiberglass but both of them are worlds ahead of steel wool.

Yeah...I'd say the packing was blow out. Replaced it with FMF 4-stroke packing and it's MUCH better now. Still has a nice, deep rumble but is much more mellow.