Not what I'd call economical if you run with the top 25% of traffic. My 91 300SE netted 17 city/19 hwy while the S420 gets 16 city/20 hwy. I prefer the car that can keep up with an ES300 when necessary.

That engine is more balanced in a 300E, that body is more balanced with a V8.

Working on that engine is like shooting fish in a barrel.

Sixto
95 S420
87 300SDL