i was looking underneath my car today, and was disgusted by the stock cat. I have a stillen y-pipe, stock cat, stillen cat-back, which has unresonated b pipe. I was wondering would it sound alot louder with an aftermarket cat, in being ricey loud, or nice growl louder. and im guessing replacing with a high-flow cat wont do wonders to my performance gains.

 

It would be ricely louder especially with an unresonated b pipe.

High flow cats do nothing really if you just have bolt ons. It would just make your exhaust look a little better.

 

for a N/A car it is pretty worthless