Hello just wondering if anyone here has experience going from a straight test pipe to a high flow cat. I would believe it would lower the volume of the car just wondering by how much? Assuming that the rest of the exhaust is 3" with a resonator and muffler on the end. I am looking to daily the evo for a while but the previous owner had a straight through test pipe which makes it just a bit louder than I'd like. It's funny because most of the time in traffic people think I'm trying to race them when I'm really only going to 2-3k rpm haha. Please let me know I am looking for an option soon I know crazy brands like ETS are what most people would recommend but I am really looking to just get one like the MAP version which I believe is 200 cell count. Thanks.

 

Get something with a gesi 200 cell, I think STM makes one with this, actually theirs is 300cell. Costly but worth it from other's reports here.

 

@RobbieOh thanks I appreciate it!

 

@thei0009 I’m running Invidia Q300 which is considered a “quiet” exhaust. I went from a ETS test pipe to ETS high flow cat. There was only a slight sound decrease to me. I would say less than 10%.

Changing your muffler or adding resonators would make more of a difference unless you go to a really restrictive cat like the stock one.