jaspirr

I recently picked up a 2010 C63. It has MHP longtube headers and stock exhaust otherwise. Previous owner thought it was too loud so he had Magnaflow hi-flow cats installed after the resonators, in an area where I'm assuming the stock secondary cats would normally be.

I politely disagree with the previous owner, and think the car needs to be louder. I can't decide if I should delete the secondary cats, or the resonator, or both. I am going to guess that a C63 with headers, no resonator, and no cats would just be obnoxiously loud. I'm probably not going to go that route.

Which would give me the best bang for the buck if I have to decide which to delete between the resonator and the cats? I am worried that just deleting the hi-flow cats won't add much noise. Definitely need a decent bump up in the exhaust noise either way. Thanks.

Petakii63

Delete secondary cats with an xpipe to balance those long tube headers. Personally, I would delete the resonator and add an akrapovic slip on. That way, you shave weight and it will sound scary, but the axle back will refine the setup. Stock mufflers are way to loud to delete everything.

OlegKouz

I personally love the sound of no cats no res + aftermarket headers, can't wait to add some headers to my setup.

Either way, will sound great!

mikeyyyallday

right now i have stock headers. but no res and no 2nd cat. both replaced by straight pipes. sounds absolutely monstrous. I'm sure a full block or 2 radius can hear your car on acceleration. may be a bit too loud for some people. so i could only imagine w/ aftermarket headers it would only be louder. i love how loud my car is now though definitely turns heads & scares the fk out of ppl sometimes.

Exotic-metal55

Delete the resonator first and see what you think, then go to cats..

DuaneC63

The secondary cats add back pressure and reduce flow. The resonator is completely flow through. Keeping it or deleting it is just a matter of sound preference. It makes no difference in performance.

OlegKouz

+63

vtune

with straight pipes over secondary cats, is it better to do x-pipe res delete or straight pipe res delete?

OlegKouz

I personally did a straight pipe res delete, but if you ask 10 people 5 of them will say x-pipe and 5 will say straight pipes, it is honestly going to be just up to you at the end.

CarHopper

^ xpipe. Straight pipes through would be pretty loud

Edit: got in after Oleg but yea, what he said.

mikeyyyallday

Yup it all comes down to your preference whether you want it ridiculous loud. Or just loud. Ridiculous loud being full straight pipes.