If the Roush Extremes are that loud inside the car, I honestly don't know if even the factory cats would make enough of a difference or not.. IIRC the factory cats on the S197 are supposedly designed to be less restrictive and higher flowing when compared to past OEM designs..
So who really knows as to how much quieter they might be or not..
The reason I'm looking to upgrade from my Magnaflow Streets is because I want the inside of my car to be more quiet, but slightly louder from the outside..
The Magnaflow Streets IMHO just don't provide enough volume from outside of the car with stock cats, but are way too loud from inside the cabin..
Anyway I'm really glad your happy with the Roush Extremes with the exception of everyone thinking that your always trying to race them at red lights lol.
However after reading over your post, I don't think the Roush Extremes are quite what I'm really looking for.. Therefore It looks as though I'll be looking into getting Borla "S" type (stingers) instead
-Thanks