BC drags or similar, or if you like the stock look, Tridents with the baffles removed, and an X-Pipe. Or if you want to forgo the X-Pipe advantage, there's the Delkevic's. Disclaimer here though I have not heard them in person.
Personally, I think the Tridents produce a deeper richer sound, the British Customs kit is loud, but doesn't produce the same sound quality.
I ran Verex headers with straight thru cocktail shakers, I like loud pipes but those were SOOO loud, now have goldie silencers, no baffles still loud but those tulip/cocktail shakers were something else, serious noise but very cheap.
Here is pic of said cocktail shakers, seems a long time ago now. Make no mistake these are the loudest pipes I have ever heard on a bobber.
Oh also you can see tank rack threaded sections welded on.( relevant to a different thread)