If you don't want to spend a ton of money, try the Emgo RoadHawks,
Quieter than Dunstalls, good look, stone cold bolt-up, about $50 each.
They're on this bike - check the "Finished Project" photos.
http://home.comcast.net/~tbpmusic/id54.htmI get them at
http://www.crc2onlinecatalog.com/Index_Main_Frame.htm - they also have Dunstalls.
If money's no object, I'm pretty sure Mac still makes 350 mufflers, 2-into-ones, as I recall. Probably $300 at least, includes new exhaust pipes.
Then there are all the exotic road-racer pipes, big bucks.