I swapped from the Perrin 2.5" catback to the CSG Touring 86 catback... It's effectively OEM+ inside the car and not very loud outside the car either.
I have a JDL UEL and ISR Overpipe, stock frontpipe. The drone with the Perrin catback between 2-3k RPM was getting old quickly, not sure why it's so bad on a 2nd gen with UEL. Local friend has it with an EL header and it's drone free, so YMMV.
The CSG Touring 86 is damn near silent inside the car, may as well be OEM+ with zero drone and not much noise. It's getting a little louder after ~100 miles but I doubt it will ever get loud. Outside the car, on video anyway, it's not as deep of a sound as the Perrin but it's also less raspy and more "wooshy"
The CSG installs a little easier than the Perrin because you can set the tip depth easily, but the exhaust clamps were installed "backwards" meaning the bolt was on the wrong side of the exhaust for maximum clearance on installation. Kinda dumb but whatever, easy to fix. I also wish the CSG was 304 stainless, big bummer that it's not.
Prior setup with the Perrin catback:
https://www.youtube.com/watch?v=-81a_fWbYpo
New setup with the CSG catback (will update when I get some miles on it like the Perrin):
https://www.youtube.com/watch?v=21KhhV9crGc
Anybody want to buy a Perrin catback? haha