any aftermarket exhaust is usually going to be significantly louder than stock. Cops may harass you even if you don't have one, the exhaust just gives them another reason to stop you. Maybe you can find some audio clips of a certain exhaust for your bike. From what i've heard D&D pipes is one of the loudest, two brothers I have no idea about.
It seems that in Denver, CO sportbikes are not that big of an issue. Maybe it's because there are plenty of twisties up in the mountains to keep us busy. Plus if you've seen the conditions of the roads here ..... There are some pot-holes so big they deserve their own zip code!!!!!!!!!