Some cars have "dual mass flywheels" - two segments separated by rubber similar to front torsional dampers than many engines have, however, AFAIK the Mercs of this era have solid flywheels.

The remaining moving part that you appear not to have changed is the clutch disk, which does have a mechanical spring/friction damper built into the hub, however, if this damper assembly failed there would probably be a lot of engagement chatter, or worse The clutch disk damper on my '81 Diesel Rabbit failed, and shortly after I realized there was a problem it became impossible to shift using the clutch, so I had to drive it to the dealer using a clutchless shift technique. If your clutch take up is smooth, the disk damper probably okay.

Mercs have relatively "rubbery" drivetrains in order to promote smoothness and damp out vibration, so they will never feel as "solid" as less expensive cars that don't have all the vibration damping features.

Maybe your best bet is to find someone with a manual transimission 124 or 201 and compare how it feels to your car. You've spent a lot of money, and you may be chasing a ghost.

Duke