I did some experimenting removing the Packing out of my Termi's. I took out 50% (still not loud enough), then 100% (too Barky, sounded like a V8 Supercar when you back off) then ended up putting back in 25%, sounds great now, just got that Loud Duke Thump.
Like scott said it's only a matter of drilling out the rivits each end & they just pull apart. Mine are round Alloy can's & only have 6 rivits each end. I Had 46,000 k's up but bought the bike second hand so don't know how long the termi's have been there. There is a fine wire mesh around the cetre perforated exhaust sleeve (which had a hole burnt in each side about 25mm round) & then a fiberglass like material around that (which was totally intact) & finally a high Temp Tape to keep it all in place. I've done it a few times now & can do the whole job start to finish in about 40mins, it's easy. I also used std (3/16") Alloy blind rivits.