I have always believed that if I were to buy loud pipes for safety, then it was time to get off the bike. I know that to some of you I am way off base. Loud pipes irritate people more than they help you. How would you feel if you were not a rider and your neighbor started up his bike early on Saturday while you were still asleep, and rapped the throttle for about 5 minutes before taking off? Or, when he returned after midnight during your work week rapping the pipes down the street. Put yourself in other people's shoes. Approaching a car and startling the driver with your pipes could cause the driver to press the accelerator, thinking you were close and were going to hit him. Not a thinking reaction, but an involuntary reflex for defense. A nice sounding after market, baffled muffler sounds really nice and would probably make your neighbor wish he was riding also. Anything disturbingly loud is more irritating than useful. My 2 cents.
I am certainly not critizing anyone who wants very loud pipes. That's you decision. That was just my thoughts. I test drove a used bike one time with loud pipes. Couldn't wait to complete the ride and get off.