The VOCSC silencer is very good for built-up areas but I find that one does lose a few mph towards the top end compared to Burgess-style silencers. I use the baffled item for town and suburbs because it's a good idea to give Joe Normal as little cause as possible to write furious letters to his local council and his representative about noisy motorbikes but if I am going for a blast or down to see the in-laws (around 600km), I put the noisy tube on for faster cruising. Not only do the natives hear me coming but they are also less likely to drive two feet from my rear number plate, trying to read what it says on the stop light...
PK
I like your last comment. I'm in favour of louder exhausts - perhaps the "I didn't see you mate" brigade will hear you instead, but then I often think that most non-motorcyclist car drivers are related to the Pinball Wizard when it comes to spotting motorcyclists.
Silencers will always be a compromise, you either stuff them full of baffles and packing, and kill the gas flow, or you cut your Burgess in half and weld in a piece of exhaust pipe and then weld up the silencer back around it, a la "road legal" racers.
Less light hearted point, in the 60s Motorcycle Mechanics (I think) had an article on a big single special (DBD34 Goldie as I remember) called Ghengis Khan (or some other vicious conquerer) it had a virtually straight through silencer with a butterfly valve type baffle controlled by a choke lever. I don't know if it worked but it might be a workable compromise.
I use the old Dunstall type, it gives me headaches, but I don't have to talk to the wife on the back.