This is something I've always wondered and played around with. It's sort of a balance...riding it properly makes a lot of noise, especially with the HK 3" pipes.

Should I be a good, quiet citizen of the roadways and lug my engine so as not to subject my fellow motorists to the sound of a stock car on crack? No...'fraid not. Why bother saying "loud pipes save lives" if you put them on and then try to drive quietly?
That being said, I decided to do what was best for my safety and my bike, so I have had no mercy on the engine this riding season as opposed to the others. Since adding the 31 tooth pulley, I shift earlier than before. I never shift at less than 3000
RPM (often 3500 RPM) regardless of what speed that may correlate to. 5th gear doesn't even get consideration until about 75 MPH. And, oddly, I do get better mileage that way.
I imagine my inability to be a good, quiet Citizen of the Blacktop makes a lot of babies cry while their mothers wince in disgust as they talk on their cell phones and balance their Starbucks MochaFrappaLattaccinos on their knees from behind the wheels of their mall-crawling Land Rovers and "green" Subarus and Toyota Prius'. Oh well...they know I'm there
RK