1st i thought i was going to delete 2ndary cats and replace the resonator with a X-pipe, get the car on the lift and guess what, no 2ndary...WIN savigs of about $100. Do the resonator/x-pipe swap...Let me just say, not what i expected, I’m actually disappointed but glad it only cost me $100. Check the link for before and after sound clip

You Tube

Get rid of the X-pipe if you want decent sound. I didn’t like straight pipes but a small H-pipe worked very well. I have no cats though.

Try

I don’t recall my car having those pre resonator things that you labeled as I.

I’d say that’s a pretty accurate assessment, maybe minus the drone with straight pipes. It’s just loud and raspy like an American truck V8 with aftermarket mufflers. As long as you keep the OEM mufflers in place you shouldn’t get any drone. I tried all three of the scenarios you listed above (without cats) and posted a thread that’s around here somewhere.

Have you tried just muffler delete and kept the resonater in and how did that sound?

There are no secondary cats on the biturbo...

No, I want the stock mufflers in place to eliminate any drone. I still need to DD this car and that includes business lunches with people that I need to converse with. I couldn’t be happier with it as is. It’s very loud with an aggressive throttle.

So you got rid of the x pipe you put in and put an H pipe in and everything else stock ?

Catless DPs, H-pipe, into stock mufflers.

There’s is a small amount of power to be had by removing cats but the rest is sound. In fact the sound going catless is worth more than any power gained to me.

I don’t think there is a “best” because what’s best for one guy isn’t best for others.

I just went went through this on my CL550 with M278 engine, so not the same engine obviously, but the straight pipes were unacceptably unrefined for me. It was obnoxiously loud and raspy with audible backfires when letting off the gas. Very unbefitting a Mercedes in my opinion and more suited to a muscle car. I wouldn’t be surprised if some passengers would ask if there’s something wrong with the exhaust. But some people love this.

I then switched from straight pipes to a x-pipe and that tamed it considerably. It’s not much louder than stock but enough to notice it has a deeper tone. i would like something a bit louder but not at the expense of a refined sound. So maybe an H-pipe is the ultimate solution - I don’t know. I’m done making exhaust mods for now.

Just dont assume one persons exhaust mod nirvana is going to be your ideal setup. There’s a lot of difference between what a 25 year old and a 50 year old will find ideal. Try to listen in person or be prepared to do this by trial and error.

And another thing I learned from all this is that you can’t really trust YouTube videos. Most phones have such crappy audio recording, you can’t get a real sense for the sound. And revving the engine while stationary is nothing like getting on the gas under load, down shifting, or coasting.

Was curious if anyone deleted the muffler only and kept the OEM resonator in for 2014 and up? If so how did you like it?

So I took it back and went straight...MUCH better at WOT and the downshifts...In my opinion, this is a much better sound than a x or h pipe