well its probably ok for you americans with your wide and straight roads lol but trust me over here in the UK its good to let car drivers know your there otherwise you can gurantee sooner or later someone will pull out in front of you and take you and your pride and joy out and i wont lay in my hospital bed saying god i wish i had a quiet exhaust but yes i do also take into consideration your points but surely the more people who can hear you comming rather than just relying on peoples inabillity to look is a good thing relying on 2 sense's is better than 1 sight and sound
Sorry but I agree with Devyl, loud exhausts just piss everyone off including me, in these days of 'green' and persecution for anything like a fast car or bike the last thing required is a loud exhaust that attracts unwanted attention.
Also where I ride (N Wales) Plod also agrees with the above
In my experience a 'replacement' exhaust when fitted with the db killer also loses performance over the standard system
Previously.........09R1, 08R1, MV1000R, MV1000S, KTM SDR (POS), MV 750S, Ducati S4, S4R, 748R, 98R1, and about 40 others........