Secondary Cat delete + resonator delete aftermarket parts?
I've been reading through the forums and checking online stores, but I can't seem to find any aftermarket parts to only replace the secondary cats (with a straight pipe) and something to replace the resonator with either (straight, H-pipe, or x-pipe).
The problem is that I don't see any individual parts to order to accomplish this while keeping everything else stock. I've seen downpipes, full exhausts, catbacks, and midpipes.
https://www.mbhmotorsports.com/produ...RoCivUQAvD_BwE
This states "This mid-section with Xpipe only works with MBH Motorsports headers . If you do not have MBH Motorsports long tube headers this IS NOT the product for you."
Local exhaust shop won't cut / replace the secondary cats with straight piping. Would love a bolt-on type solution here. Can anyone point me in the right direction?




I'd even be willing to get a full exhaust that started AFTER the first catalytic converters (in the downpipes) but it doesn't seem to be an option. I wouldn't mind going with downpipes but I have a Maxcare warranty for 5 years, so i don't want to add ECU tune, downpipes, or anything else that's changes that much. I just want to open it up a bit more. Sounds nice WOT and downshifts sounds really amazing, but there's not much in between that.
Are there catbacks that I can get that still retain the AMG sound but are louder? I really do like the exhaust valve but wish I could disable it completely when I want to.




I'd say if you're concerned with the warranty, just don't do anything. I used to work at a shop and we'd see warranties deny claims for the slightest modification, even if it had nothing to do with a failure. If they see anything cut under there, it really is no different than if you had downpipes on for a lot of them. And if you don't cut anything, you can always swap it back to stock if you had some warranty concern crop up and had time to make the switch back just to avoid the possibility of problems.
Check out kenny's video on Youtube for the muffler mod?
I would also say, most modifications like removing resonator or swapping (or deleting) mufflers will change the sound character. Downpipes will too as far as tone and loudness, but will be the closest to the stock character. Downpipes w/ aftermarket cats maybe? Although you have to be careful on brands/quality.
W212's with the M157 (MY2012-16) only come with ONE set of Cats. No secondary cats.
Most simply do a resonator delete to slightly increase exhaust volume. As mentioned above, look at linked video and you will find out of unrestricted the stock exhaust already is. The only "restriction" in the exhaust path are the Catalytics.
Some companies make "true" turbo back downpipes/exhaust systems that replace the Bridge pipes. I guess the stock ones could be called restrictive when compared to some aftermarket ones.
I think I'll start with the resonator delete and going with an x-pipe. Would another (h-pipe or straight pipe) keep the same AMG noise but make it louder? I don't want to change the sound itself, just the loudness. WOT sounds pretty good but I can barely hear the thing just cruising around which I know is partly related to the exhaust valves opening at certain RPMs.
I'd say if you're concerned with the warranty, just don't do anything. I used to work at a shop and we'd see warranties deny claims for the slightest modification, even if it had nothing to do with a failure. If they see anything cut under there, it really is no different than if you had downpipes on for a lot of them. And if you don't cut anything, you can always swap it back to stock if you had some warranty concern crop up and had time to make the switch back just to avoid the possibility of problems.
Check out kenny's video on Youtube for the muffler mod? https://youtu.be/rS5yrcBNuVY?si=i9EC145UAOIOn_nm
I would also say, most modifications like removing resonator or swapping (or deleting) mufflers will change the sound character. Downpipes will too as far as tone and loudness, but will be the closest to the stock character. Downpipes w/ aftermarket cats maybe? Although you have to be careful on brands/quality.
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Last edited by Tooken; Sep 30, 2023 at 09:56 PM.
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The real sound changes come from de-cat or high-flow cats. The rest of the exhaust is pretty open and doesn't do much except for the great tuning in the resonators done by the factory to prevent drone.





