You only get rasp when you switch out the stock cats with high flow ones. I had Berk, and then switched back to stock because of rasp (when given a good amount of throttle) and loudness.
The 12" one drones quite a bit after a long hot drive, and it's between 2k-3k RPM as others described. Past 3k to redline it is very quiet. At idle after warming up it burbles, and it sounds pretty freaking cool
The video below was when I had the Berks, so you can hear what the rasp is like: