Is there a company like Brabus or Renntech that makes an exhaust system for the C55 AMG?

 

There are but I don't think they offer much of any performance gain at all. There are a few members here (hooleyboy) that have gone the custom exhaust route in addition to proper tuning and have seen some results. You will probably see more gains just deleting your secondary cats.

 

Probably the best headers out there are from Hooleyboy. He threw an E55 supercharger on his C55 and then got involved in tuning and fabricating. HIs exhaust guy has some of the best work I've ever seen.

Check out his Long tube headers. Not cheap, but I'm sure you can see why.

https://mbworld.org/forums/c32-amg-c55-amg-w203/306679-official-c55-long-tube-header-release.html

https://mbworld.org/forums/c32-amg-c55-amg-w203/303719-truth-about-headers.html

https://mbworld.org/forums/c32-amg-c55-amg-w203/308362-c55-long-tube-header-update.html

 

I am not too concerned with performance gains right now, I am really just looking for something that will provide a little more aggressive and louder sound.

 

Ah.........OK, I was just going by the thread title.

Just get rid of your secondaries then.

 

Get rid of your secondary cats or just remove your resonator.

 

In my own opinion, Eisenmann makes very good sound for Mercedes Benz.
I deleted my resonator and I am satisfying with the sound.
I can't really here it from inside but I can hear its growling when I open window at parking lots or inside of tunnel.

 

For a C55, I'd say Kleemann or MBH headers for performance and sound, deleted resonator and/or 2nd cats for sound increase/improvement per dollar.