Originally Posted by m3alabama
Did you read my post? HFC is quieter than an ACM mod in every way except HFC is much higher pitched and has no drone.
No CEL with active xpipe which I have.
Yes read your post but not sure what it has to do with what I am asking. I have the traditional 2 pipe oem mod, not the acm version. Also HFC = high flow cats correct? As I stated, I am not interested in messing with my primary cats, just looking for input from anyone who has removed secondary cats and what they thought of the results.