Thats one of the biggest myths that a louder pipe will make drivers around you more aware of you. It doesnt change s**t. If you count on that you will be dead very soon!
That sums it up:
"" The "loud pipes save lives" argument is one I see or hear on almost a weekly basis. It's usually coming from some guy on a Harley or retro Triumph, though the sportbike guys are jumping on as of late. I honestly can’t tell if people really believe it, or it's just a nice justification when someone says their bike is too loud, but I think it's the second dumbest thing commonly heard from riders. (If you're wondering, the first is that 600cc supersports are beginner bikes.)
Let's start with some basic physics and a little rationality. Your exhaust is pointed backwards and by the nature of you traveling forward, you're actually leaving the sound behind you as you move forward. If that concept is confusing, think of the sound of a fire truck passing you with its siren blaring. The siren is pointed forward because the purpose is to warn driver’s the truck is approaching from behind. The next time you hear one coming, notice that it’s louder when it’s coming toward you than when it’s going away.
Now apply that to motorcycle crashes. The one comprehensive, reliable study of motorcycle crashes in this country is the well known "Hurt Report," which is now nearly 40 years old. Harry Hurt and his team found that 64.9 percent of multiple-vehicle motorcycle crashes were the fault of the car driver and “the typical accident in this category is portrayed by the automobile in traffic turning left into the path of the oncoming motorcycle.” A lot has changed in 40 years, but one thing that I think we can all agree hasn’t changed is that the car drivers are still pulling out in front of us. That means the bigger danger is still ahead, not behind, but most of the racket from loud pipes is just pissing off the people behind you, while doing very little to warn those in front of you.
Your headlights and horn, however, are pointed ahead. If you really were so concerned with an upgrade that could save your life, you’d add aftermarket auxiliary lights and upgrade your horn. But then you’d run the risk of looking like a dork instead of sounding like a badass.""