Check into the Q series silencer. Improves your tractablility and keeps it quiet. On the otherhand, you can by quality packing material and keep your stocker fresh. Keeping your silencer service will help keep your engine running consistant and quiet.
RideStealth/LoudSucks
if you have a race bike and want to ride in the woods. your gonna need a spark arrester. which is why i bought one.
but if i wasnt riding in the woods, i probably wouldnt had bought a new silencer.
In my limited experience, loud competition "silencers" can make the bike feel more peppy and responsive; especially at lower RPM. I suspect certain loud "silencers" can add some overall power also. I have a PC 296 and it's probably as loud as I'd go for off-road.