There's sounding nice and then there's way to loud.
For sure. There's that beautiful rumble and growl, then there's obnoxious! On a KLR adding a pipe is nothing but extra noise as it's never going to be much faster (unless you're big bore kitting and the rest at the same time). I prefer quiet on the dual sport especially on the trails as it keeps you a little more under the radar.
The Ninja on the other hand will be getting a full Yoshi or Akro system at some point!