you mean str8 piped my friend, at a minimal cats removed if you still have mufflers, and even those may be gutted :p got a 2010 cl63 x-pipe/res delete & flow pack mufflers... that raw sound is at least the CATS off, and my guess is res or muff delete also... either way enjoy!!!
Not stock- real mufflers was deleted and replace in that place straight pipes I think. Low RPM range was tragedy- I have the same in my CL63, replace it for X-PIPE its better idea ;)