"Legit reason" has to be at least "reasonable suspicion", and that is pretty clearly defined. I have never stopped anyone for loud exhaust in my life, but as an example, last night, I was on the freeway, and a guy went by me doing 90 in a 55, cut me off, then cut off 3 other cars before I caught up to him. I pulled him over and he was drunk, and didn't even see me when he passed me. What I observed gave me more then "reasonable suspicion" since he already committed a criminal act in front of me, so at that I time had probable cause to stop and make an arrest just based on what I saw. The fact that he was drunk once stopped just adds another charge.
Profiling is making a stop based solely on someone's appearance, race, religion, creed etc. However, at times, profiling is appropriate, but it has to be supported by case law, or the criteria used for that specific profiling incident has to be clearly established by current law enforcement standards and practices. For example, especially in AZ, and I'm gonna assume Texas and California, we have the ability to profile people as "Sinaloa Cowboys". If you see a vehicle, occupied by a Hispanic male, with clear indicators of cartel affiliation (Crossed AK47s sticker on the back window, CDS with skull and bones sticker, La Santa Muerte hanging off the rear view etc or a combination of multiple indicators of said affiliation), you can assume that guy is not here to just make a nice living for himself and his family using legal means. Even in that case, we still wait for a traffic violation before a stop is initiated, just due to the fact if anything does come of the stop, it will make for a stronger case in court.
Getting pulled over for a car being too loud is chicken shit and a waste of time. There are worse things going on out there....well maybe not in Canada
