I do drive a 190E 2.6 automatic with a Sportline chassis as my daily thrash & while it is a fine car, IMHO it is not a substitute for a 16v. Different kettle of fish entirely.
I guess the point is - a 16v is the performance choice, in which case you'd opt for a manual transmission (as the vast majority did )
If you want a quick, comfortable car with an autobox - the six-pot 2.6 is the better choice.
A 16v auto will never be as quick or controlled as the manual counterpart - and are much less desirable as a result.
Slot a 3.0 M103 into a 2.6 auto and you're pretty much spoiled!