Catted Ca Catless Longtubes
 

Just curious on noise level difference. I have the MBRP Raceback. About to pull the trigger on a set of 1 7/8” Kooks and can’t decide if I want to get the high flow cats or just go catless. Is the noise level significantly different between the two?

I can tell you right now, i just got TSP 1 7/8th headers catless installed on my mbrp race axle back and the thing SCREAMS anything above 2500 RPM's. It's honestly not the for the every day driver if you cant stand a lot of cabin noise. But if it does not bother you then go for it

I have American Racing 1 7/8 headers and started catless but eventually went with some Vibrant Gesi High flow cats.



The Highflow cats won't really make much of a difference in the volume of the sound but will refine it in a good way, reduce or eliminate any rasp and eliminate that awful smell that no cats force you to deal with.

all my rides are catless. I absolutely love the sound of a cammed headers without cats thru exhaust. you can't go worng

My car ran like shiznett and sounded like rusty tin can with no-cats, I have headers and have gone from mild to wild. Putting cats in was the best single mod I have ever done. I was going to do it anyway I just wanted the tune correct. no-cats sound like cheap Mustang exhaust IMO of course.

Yea this is exactly what I wanted to hear. Not a fan of the rasp but I can live with some of it. Really just don’t want to smell the gas fumes (been there done that).

i have afe power longtubes with cats and they told me in cali both are illegal so it doesnt really matter but you dont really need catless unless your running alot of e85 or race gas and cats/hi flow cats not gonna be a huge power difference

My car like your is a M6, IMO the M6 with no cats at low RPM sounds like a rusty Mustang exhaust. You will feel the same way... Put cats in smooth like butta… still sounds great. As noted I've gone from mild to crazy....

Do you need to get the car retuned if going from a catless setup initially to a catted one?

Some tuners turn off the rear o2 no matter what. There are smog reddy codes that never turnoff...soifyou have to pass smog...