After a bit of advice............ I've just discovered my large Duratec caterham silencer could do with new packing as when its held up you can hear the packing sliding up and down in the can, I'd say about a third of the packing is gone judging by this. The car sounds ok as in its not overly noisy. Its an original polished Cheeseman silencer and is riveted at the front, my question is has anyone drilled off the rivets and opened one of these up successfully? I don't want to drill them off to find its a hammering session to open up and in doing so, not worth it as I'll do more damage than good! If its ok to do I'll get some Acousta-fil, some new stainless rivets and re-do it. Thanks