I received my catless down pipes for my c63 coupe and not sure if I want to proceed installing after coming from a CLA45 with catless downpipes, it made the cabin not breathable, how are you guys feeling about it?

 

If you never plan to put windows down or opening sunroof while driving, then you will be fine.
Otherwise, you will suffer same smell as in CLA45.

I ordered catted downpipe so that I don't have to deal with smell.

 

Im running catless and it never bothered me not even my passengers mention anything and i roll with every window wide open in the city. The only time you can smell is when there's some back wind.

 

We came up on an M4 this past weekend doing a little over the speed limit. We could smell him. Catless. My wife was driving. So as we pass him, he punches it. My wife not wanting to be embarrassed puts it in Sport and buries the pedal. Gone! Never looked back. Love this woman!

BTW, she's 68...

 

I have catless downpipes in stock

 

I have been running Weistec "catless" downpipes since March and the only time I notice any fuel smell is when slowly backing into my garage.
And actually I have gotten used to it and barely notice it even when backing into the garage now unless it takes me a few minutes to get it into the garage just right.

But driving around with windows up or down I have NOT noticed any smell really...maybe a little bit if sitting in traffic with windows down??? But with windows up and A/C on I never smell anything.

Added note: I have two Weistec "Stage 2" tunes...one for pump gas (crappy 91 octane) and one for Race Fuel (for when I run 1/2 mile events).
And whenever running my Race Fuel tune and backing into my garage the fuel smell is a good thing...Race Fuel smells Sooooo Good...LOL

 

Its really not that bad. Doesn't bother me at all windows up or down.

 

ya the smell of fuel once in awhile, but i like the smell. its faint but its there

 

 

I have catless down pipes and it doesn't bother me at all. If the windows are up I never smell anything. Only time I smell it is when I am in the garage. Occasionally if I have the sun roof open or windows down I will get a little draft but nothing that really ever bothers me. Smells don't bother me as much as some people so it isn't a big deal to me. If you have a sensitive nose then I would just stay stock or get high flow cats.

 

And to be honest with things like this, every car will have a different result, since there are so many variables, mostly with tunes, etc..
if you are comparing Apples to Apples, same model, options etc etc, you would/could still get different results with this..

With that being said, you always are open to getting "the smell" if you remove cats... .period... you could get lucky and have no noticable smell, while you might get an overwhelming result. (too many variables, options to compare 1 to 1)

My 2016 C63s , with AWE switch path, Renntech Stage 1 ECU , Modal Works Intakes, Renntech BOV - sounds and acts like a complete BEAST .. I have had friends with the same car, put the same exhaust etc on there cars, and they sound completely different.
( I have a new gopro coming and will do a under hood video, while driving for the Modal Works intakes <- I want to capture the sound of those)

I have not done the Down Pipes yet, as I am trying to decide on the Pro's Con's for it.. I will NOT due cat-less , so what benefit do I get with replacing with aftermarket other then just weight ?? I am not looking to get every inch of HP out of the car, as I use it as a DD.
(for longevity reasons, I am getting 3rd party inner coolers etc , never hurts to keep things cool)

 

I have catless and when I first installed them I really didn't smell anything but as time passed on I started to notice it when I have the windows down sitting at red lights or doing about 20-30mph. So I try to keep a lot of air fresheners in the car lol