I think your comments about the engine sound of a four cylinder is correct.
All four cylinder engines will never idle as smoothly and have the same harmonious engine growl as our inline 6.
An inline 6 is a perfectly balanced engine, and an inline 4 is not.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".