Guess it's different when your Mustang isn't your daily driver, but I for one love the fact that the S-trim is louder than the SQ. It's for sure a head turner on the street, and for sure when I pull into the weekend car show over here. It's not so loud that it can annoy you imo, unless you spend a lot of time idling, and once under load you can't hear it over your exhaust anyways...but peeps outside still certainly can! In terms of outflowing between the two, 10lbs and under, it's a matter of a few rwhp (5 at the absolutely most according to dynosheets I've seen with similar setups). Also, it's great to see all the weird faces peeps in the other lanes give when I pull up next to them, trying to figure out why the car is that noisey....
)