I drove my friend's 2011 E63 today. Interesting how much different the E feels compared to the C. First thing I noticed is the how much quieter the exhaust is.

We both have stock exhausts. Is the E class just insulated better? Besides being quieter the note seemed a little subdued as well.

 

My 2010 E63 has completely stock exhaust system and to me it's the perfect degree of loudness, mostly subdued while cruising but damn it really roars to life when you stomp on it. Brings constant grins to my face.

 

the E63 has larger mufflers which dampen the noise more while still flowing. the other difference is the E63 has 3 inch piping whereas the C63 has 2.75 inch piping.

haven't seen anyone cut open a E63 muffler, but i'm also believing the piping is chambered and includes a J pipe within which further dampens the ugly frequencies and also allow for a completely quiet cruising volume even when straight piped with LTH and minus resonators.