Silencer packing

[Sirflopsalot]

I have a Kawi 750sx with a
Coffman pipe and an aftermarket silencer. While I enjoy the muffled scream of a 2 stroke of the water my neighbors are less then impressed. Has anyone found a decent waterproof packing material for a silencer?

 

[CARBONX2]

Rather convert it to a centre-bleed pipe, noise problem solved

 

[X2Kid]

Go back to the stock waterbox? All of my 'ski's (2 Superjets, 2 X2's) run aftermarket pipes (all different) with stock waterboxes and none of them are much louder than stock. Technically one of them does run an aftermarket waterbox (Factory Pipe on the squarenose), but it's similar in design to a stock one off of a roundnose.